阅读说明：本技术 安全文档及其制造方法 (Security document and method for producing same ) 是由 T·马提尼 G·里特 J·加尼耶 R·拉格罗恩 P·韦亚 于 2020-05-18 设计创作，主要内容包括：本发明涉及安全文档的技术领域,所述安全文档包括如窗口式安全线、安全箔、安全片、全息图或墨印刷的安全特征等安全特征和保护性涂层,以及所述安全文档的制造方法。该安全特征具有至少约5μm(微米)的安全特征厚度t-(f)和背向基材的安全特征表面,所述安全特征表面由与该安全特征的边缘相邻的第一区域(120b1)和与该安全特征的边缘不相邻的第二区域(120b2)构成。保护性涂层(130A,130B,130C)覆盖背向基材的安全特征表面、与安全特征相邻的第一基材表面(110c)、和第二基材表面(110a),所述第二基材表面(110a)不同于由安全特征覆盖的基材表面和第一基材表面。覆盖背向基材的安全特征表面和第一基材表面的保护性涂层为透明的,覆盖第一区域(120b1)的保护性涂层(130B)具有厚度t-(b1),覆盖第二区域(120b2)的保护性涂层(130B)具有厚度t-(b2),覆盖第一基材表面(110c)的保护性涂层(130C)具有厚度t-(c),并且覆盖第二基材表面(110a)的保护性涂层(130A)具有厚度t-(a)。厚度t-(c)大于厚度t-(f),厚度t-(f)大于厚度ta；厚度t-(b2)大于厚度t-(a)；并且厚度t-(c)大于厚度t-(b1),厚度t-(b1)大于或等于厚度t-(b2)；或者厚度t-(c)等于厚度t-(b1),厚度t-(b1)大于厚度t-(b2)。安全文档的表面上的可变保护性涂层厚度为本发明的安全文档提供了对来自环境的物理和化学损害的提高的耐受性,同时保持了这种安全文档所需的机械耐受性。(The invention relates to security documentsIncluding security features such as windowed security threads, security foils, security sheets, holograms or ink printed security features and protective coatings, and a method of manufacturing the security document. The security feature has a security feature thickness t of at least about 5 μm (microns) f And a security feature surface facing away from the substrate, the security feature surface being comprised of a first region (120b1) adjacent an edge of the security feature and a second region (120b2) not adjacent the edge of the security feature. A protective coating (130A, 130B, 130C) covers a surface of the security feature facing away from the substrate, a first substrate surface (110C) adjacent to the security feature, and a second substrate surface (110A), the second substrate surface (110A) being different from the substrate surface and the first substrate surface covered by the security feature. The protective coating covering the surface of the security feature facing away from the substrate and the surface of the first substrate is transparent, and the protective coating (130B) covering the first region (120B1) has a thickness t b1 The protective coating (130B) covering the second region (120B2) has a thickness t b2 The protective coating (130C) covering the first substrate surface (110C) has a thickness t c And the protective coating (130A) covering the second substrate surface (110A) has a thickness t a . Thickness t c Greater than thickness t f Thickness t f Greater than the thickness ta; thickness t b2 Greater than thickness t a (ii) a And a thickness t c Greater than thickness t b1 Thickness t b1 Greater than or equal to thickness t b2 (ii) a Or thickness t c Is equal to thickness t b1 Thickness t b1 Greater than thickness t b2 . The variable protective coating thickness on the surface of the security document provides the security document of the present invention with increased resistance to physical and chemical damage from the environment while maintaining the mechanical resistance required for such security documents.)

1. A security document (100) comprising:

a base material (110) having a base material,

a security feature (120) applied to or inserted into a portion of the substrate (110), wherein the security feature (120) is selected from the group consisting of windowed security threads, security foils, security sheets, holograms and ink printed security features, having a security feature thickness t of at least about 5 μm (microns)_fAnd a security feature surface (120) facing away from the substrate (110)_b) Said security feature surface (120)_b) By a first region (120) adjacent to an edge of the security feature (120)_b1) And a second region (120) not adjacent to an edge of the security feature (120)_b2) Is composed of, and

a protective coating (130A, 130B, 130C) covering

The security feature surface (120) facing away from the substrate (110)_b)，

A first substrate surface (110)_c) Adjacent to an edge of the security feature (120), an

A second substrate surface (110)_a) Different from the substrate surface covered by the security feature (120) and the first substrate surface (110)_c)；

Wherein

Covering the security feature surface (120) facing away from the substrate (110)_b) And the first substrate surface (110)_c) Is transparent,

covering the first area (120)_b1) Has a thickness t_b1,

Covering the second area (120)_b2) Has a thickness t_b2，

Covering the first substrate surface (110)_c) Has a thickness t_cAnd is and

covering the second substrate surface (110)_a) Has a thickness t_a；

It is characterized in that

Said thickness t_cGreater than said thickness t_fSaid thickness t_fGreater than said thickness t_a；

Said thickness t_b2Greater than said thickness t_a；

And is

Said thickness t_cGreater than said thickness t_b1Said thickness t_b1Greater than or equal to the thickness t_b2；

Or said thickness t_cIs equal to the thickness t_b1Said thickness t_b1Greater than said thickness t_b2。

2. The security document (100) according to claim 1, wherein said thickness t_aLess than about 5 μm, preferably between about 1 and 3 μm.

3. The security document (100) according to claim 1 or 2, wherein said thickness t_cGreater than or equal to the thickness t_fAnd said thickness t_b2The sum of (a) and (b).

4. The security document (100) according to any one of claims 1 to 3, wherein the security feature surface (120) facing away from the substrate (110) is covered_b) And the first substrate surface (110)_c) And covering the second substrate surface (110)_a) Each of said protective coatings (130A) being obtained from a different curable varnish.

5. The security document (100) according to any one of claims 1 to 4, wherein the cover faces away from the substrate (11)0) The security feature surface (120)_b) And the first substrate surface (110)_c) The transparent protective coating (130B, 130C) of (a) consists of a single layer.

6. The security document (130) according to any one of claims 1 to 5, wherein the second substrate surface (110) is covered_a) Is a matte finish and/or covers the security feature surface (120) facing away from the substrate (110)_b) And the first substrate surface (110)_c) Is a flash paint.

7. The security document (100) according to any one of claims 1 to 3, wherein the protective coating (130A, 130B, 130C) is constituted by a single transparent layer.

8. The security document (100) according to any one of claims 1 to 7, wherein the portion of the substrate (110) to which the security feature (120) is applied is a transparent polymer.

9. The security document (100) according to any one of claims 1 to 7, wherein the second substrate surface (110)_a) Comprising the security document (100) except by the security feature (120) and the first substrate surface (110)_c) The substrate surface on both sides other than the covered substrate surface.

10. A method of manufacturing a security document (100) according to any one of claims 1 to 9, comprising the steps of:

a) providing a security document (100') comprising:

a base material (110) having a base material,

a security feature (120) applied to or inserted into a portion of the substrate (110), wherein the security feature (120) is selected from the group consisting of windowed security threads, security foils, security sheets, holograms and ink printed security features, having a security feature thickness t of at least about 5 μm (microns)_fAnd back to the instituteThe security feature surface (120) of the substrate (110)_b) Said security feature surface (120)_b) By a first region (120) adjacent to an edge of the security feature (120)_b1) And a second region (120) not adjacent to an edge of the security feature (120)_b2) Forming;

b) inkjet printing a radiation curable varnish on the security feature surface (120) facing away from the substrate (110)_b) And a first substrate surface (110) adjacent to an edge of the security feature (120)_c) Wherein the first substrate surface (110)_c) Is equal to or higher than the first area (120) adjacent to the edge of the security feature (120)_b1) A varnish deposit on, and the first region (120)_b1) Has a varnish deposit equal to or higher than the second region (120)_b2) A varnish deposit on; and

c1) printing the curable varnish on the surface of a second substrate by offset or flexographic printing (110)_a) Said second substrate surface (110)_a) Different from the substrate surface covered by the security feature (120) and the first substrate surface (110c), and optionally printed on the security feature surface (120) facing away from the substrate (110)_b) And the first substrate surface (110)_c) The above step (1);

or

c2) Ink-jet printing a radiation curable varnish onto a second substrate surface (110)_a) Said second substrate surface (110)_a) Different from the substrate surface covered by the security feature (120) and the first substrate surface (110)_c)；

And

d) curing the curable varnish to provide a covering of the security feature surface (120) facing away from the substrate (110)_b) The first substrate surface (110)_c) And the second substrate surface (110)_a) The protective coating (130A, 130B, 130C);

wherein the second region (120)_b2) Above the second substrate surface (110)_a) Varnish deposit on.

11. The method of manufacturing of claim 10, wherein step c1) is performed before step b).

12. The method of manufacturing of claim 10, wherein step b) is performed before step c1), and further comprising step e) performed between steps b) and c 1).

e) At least partially curing the radiation curable varnish printed in step b).

13. The manufacturing method according to any one of claims 10 to 12, wherein in step c1), the curable varnish is printed only on the second substrate surface (110)_a) The above.

14. The method of manufacturing of claim 10, wherein the method of manufacturing comprises the steps a), b), c2), and d).

15. The manufacturing method according to any one of claims 10 to 14, wherein the varnish deposit on the second substrate surface is less than 5g/m²Preferably from about 1 to about 3g/m²In the meantime.

Technical Field

The present invention relates to the field of security documents, including security features such as windowed security threads, security foils, security sheets, holograms or ink printed security features and protective coatings, and methods of manufacturing said security documents. The security document according to the invention exhibits an improved resistance to physical and chemical damage from the environment.

Background

With the continuing improvement in the quality of color copies and prints and the attempt to protect security documents such as banknotes, value documents or cards, traffic tickets or cards, tax banderoles (tax banderoles) and merchandise labels from counterfeiting, tampering or illicit reproduction, it is common practice to incorporate various security features into these documents. Typical examples of security means include security threads, windows, fibres, metal plates (planchettes), foils, sheets, labels, holograms, watermarks, security features obtained from security inks including security materials such as magnetic pigments, UV absorbing pigments, IR absorbing pigments, optically variable pigments, light polarizing pigments, photoluminescent pigments, electrically conductive pigments and surface enhanced raman spectroscopy particles.

It is known to provide security documents, in particular banknotes, with an anti-soiling protective coating to extend their lifetime and to be suitable for circulation. The protective coating is a protective layer facing the document environment, which is obtained from heat-curable varnishes, radiation-curable varnishes and combinations thereof.

European patent application publication No. EP0256170a1 proposes a currency paper printed with an ink containing 1-10% by weight of micronized wax and coated with a protective layer consisting essentially of a cellulose ester or cellulose ether. The protective layer is applied to the surface of the currency paper by spraying, dipping or roller coating to provide a protective layer of constant thickness.

U.S. patent application publication No. US20070017647A1A security paper for producing value documents is provided, which has a flat substrate which is at least partially provided with an anti-soiling protective layer for extending the service life and being suitable for circulation. The disclosed protective layer comprises at least two paint layers, a first lower paint layer, which is formed by a physically drying paint layer applied directly on the paper substrate, for closing the pores of the paper substrate, and a second upper paint layer, which protects the substrate from physical and chemical influences. The first lower paint layer is 1-6 g/m²Preferably 2 to 4g/m²The constant coating weight of (a) being present on the substrate and the second topcoat being present at 0.5 to 3g/m²Preferably 1 to 2g/m²Is present on the substrate.

International patent application publication No. WO2014067715a1 teaches imparting stain resistance to security documents comprising a substrate by applying a radiation curable protective varnish comprising a cationically curable compound and a fluorinated compound on the substrate. The radiation-curable protective varnish is applied by screen printing or flexographic printing to ensure a constant protective layer thickness below 5 μm, preferably between 1 μm and 3 μm. For security documents comprising a security feature, the radiation curable protective varnish may or may not be applied on the surface of the security feature.

Canadian patent application publication No. CA2446559a1 describes a long-life security paper comprising a security element, wherein the security paper is covered by a matte protective lacquer layer, which is omitted on the surface of the security element. The surface of the security element may be covered by a layer of a flash protective lacquer. If the security paper is covered by both a matte protective lacquer and a sparkling protective lacquer, the lacquers are printed by flexography at every m²2-8 g liquid lacquer, or by screen printing in an amount per m²An amount of 5-15 grams of liquid lacquer is applied and the printing step is performed in a register accurate manner to provide a protective lacquer layer of constant thickness on the surface of the security element and the remaining surface of the security paper.

Security threads, foils, sheets, holograms and ink printed security features have been widely used as security features in security documents, particularly banknotes. These security features are manufactured separately and either integrated into the security document during its manufacture (e.g. security threads, security foils, security sheets, holograms) or printed on the security document during its manufacture (e.g. ink printed security features).

The security threads, foils and sheets are manufactured on a roll of substrate by several techniques selected from the group of printing, coating, vapour deposition, etching, lacquering and/or combinations thereof, which are eventually cut into security threads, foils and sheets to be inserted into the security document substrate (e.g. security thread) during the manufacture of the security document or applied onto the security document substrate (e.g. security foil, security sheet) by gluing or hot embossing.

Holograms are diffractive optically variable security features that can be integrated in windowed security threads, security foils, security sheets, or applied to a security document substrate, for example on a transparent window of a security document.

The ink-printed security feature is a security feature obtained by printing on a security document a security ink comprising one or more security materials selected from the group consisting of magnetic pigments, UV absorbing pigments, IR absorbing pigments, optically variable pigments, light polarizing pigments, photoluminescent pigments, electrically conductive pigments, surface enhanced raman spectroscopy particles and plasmon resonance particles.

Due to the thickness of security threads, foils, sheets, holograms and ink printed security features of up to 50 micrometers, and/or the difference in their surface (surface energy, smoothness, etc.), currently available protection methods for security documents comprising such security features based on the application of a protective coating with a constant thickness by flexography, offset printing or screen printing are not sufficient to prevent the degradation of these security features compared to the adjacent surface of the security document substrate. In particular, the edges of these security features are directly exposed to the environment and its mechanical and chemical damages, which leads to a deterioration of the security features.

The protective coating applied by flexographic printing is characterized by a substantially constant coating thickness. Since the thickness of the protective coating applied by flexographic printing is generally between 2 and 3 microns (corresponding to 2.0 to 3.0 g/m)²The protective varnish composition having a coating layer comprising1～1.2g/cm³Typical densities in the range) such protective coatings are typically too thin to effectively protect security features, such as windowed security threads, foils, sheets, holograms and ink-printed security features, which typically have a thickness of at least about 5 micrometers (μm).

The same problem is encountered when using protective coatings applied by offset printing.

The protective coating applied by rotary or flat screen printing is characterized by a substantially constant coating thickness that is significantly greater than the thickness of the protective coating applied by flexographic or offset printing. The protective coating applied by screen printing has a typical thickness equal to or greater than 10 microns (corresponding to 10-15 g/m)²Has a protective varnish composition of from 1 to 1.2g/cm³Typical densities within the range). Such large protective coating thicknesses potentially ensure satisfactory protection of certain windowed security threads, foils, sheets, holograms and ink printed security features. However, due to the hardness of the thick protective coating, a thick protective coating applied over the entire surface of the security document leads to significant mechanical resistance problems of the protected security document, for example in a crumple test. To avoid compromising mechanical properties, the protective coating covering the entire surface of the security document should have a thickness of less than about 5 micrometers (μm). In addition, printing a thick protective coating results in a higher manufacturing cost for the protected security document.

Accordingly, there remains a need for security documents, in particular banknotes, comprising a security feature selected from the group consisting of windowed security threads, security foils, security sheets, holograms and ink printed features characterized by a thickness of at least about 5 micrometers (μm), which exhibit an improved resistance to physical and chemical damage from the environment while maintaining the required mechanical resistance of such security documents. Furthermore, there is still a need for a cost-effective and time-saving manufacturing method of such a security document.

Disclosure of Invention

It is therefore an object of the present invention to provide a security document comprising a security feature selected from the group consisting of: windowed security threads, security foils, security sheets, holograms and ink printed security features and characterized by a thickness of at least about 5 μm (micrometers) exhibit improved resistance to physical and chemical damage from the environment when compared to prior art security documents while maintaining the mechanical resistance required for such security documents. This is achieved by a security document as claimed herein, comprising:

a base material, a first metal layer and a second metal layer,

a security feature applied to or inserted into a portion of the substrate, wherein the security feature is selected from the group consisting of windowed security threads, security foils, security sheets, holograms and ink printed security features, having a security feature thickness t of at least 5 μm (microns)_fAnd a security feature surface facing away from the substrate, the security feature surface being comprised of a first region adjacent an edge of the security feature and a second region not adjacent the edge of the security feature, and

protective coating, covering thereof

A surface of the security feature facing away from the substrate,

a first substrate surface adjacent to an edge of the security feature, and

a second substrate surface different from the substrate surface covered by the security feature and the first substrate surface;

wherein

The protective coating covering the surface of the security feature facing away from the substrate and the surface of the first substrate is transparent,

the protective coating covering the first area has a thickness t_b1，

The protective coating covering the second area has a thickness t_b2，

The protective coating covering the first substrate surface has a thickness t_cAnd is and

the protective coating covering the second substrate surface has a thickness t_a；

It is characterized in that

The above-mentionedThickness t_cGreater than said thickness t_fSaid thickness t_fGreater than said thickness t_a；

Said thickness t_b2Greater than said thickness t_a；

And is

Said thickness t_cGreater than said thickness t_b1Said thickness t_b1Greater than or equal to the thickness t_b2；

Or said thickness t_cIs equal to the thickness t_b1Said thickness t_b1Greater than said thickness t_b2。

The variable protective coating thickness on the surface of the security document has a greater coating thickness (t) on the first substrate surface adjacent the edge of the security feature and a first region of the security feature surface facing away from the substrate than on the remaining surface of the security document_c，t_b1) Wherein the thickness t of the coating on the first substrate surface_cGreater than the thickness t of the security feature_fAnd is greater than or equal to the coating thickness t on the first region_b1Thereby providing the security document claimed herein with increased resistance to physical and chemical damage from the environment when compared to security documents comprising similar security features of the prior art. Due to the large coating thickness (t)_c，t_b1) Only on the first substrate surface adjacent to the edge of the security feature and on the first area of the security feature surface facing away from the substrate, i.e. on a very limited surface of the security document, the mechanical properties and manufacturing costs of the security document are not affected, since this is the case for security documents having a large coating thickness over the entire surface of the security document.

Further claimed and described herein is a method of manufacturing a security document as claimed herein, comprising the steps of:

a) providing a security document comprising:

a base material, a first metal layer and a second metal layer,

applied to or inserted into said substrateA security feature in a part of (a), wherein the security feature is selected from windowed security threads, security foils, security sheets, holograms and ink printed security features, having a security feature thickness t of at least 5 μm (micrometres)_fAnd a security feature surface facing away from the substrate, the security feature surface being comprised of a first region adjacent an edge of the security feature and a second region not adjacent the edge of the security feature;

b) inkjet printing a radiation curable varnish onto the surface of the security feature facing away from the substrate and a first substrate surface adjacent an edge of the security feature, wherein the varnish deposit on the first substrate surface is equal to or higher than the varnish deposit on the first region adjacent the edge of the security feature and the varnish deposit on the first region is equal to or higher than, preferably higher than the varnish deposit on the second region;

and

c1) printing a curable varnish by offset or flexographic printing on a second substrate surface, different from the substrate surface covered by the security feature and the first substrate surface, and optionally on the security feature surface facing away from the substrate and the first substrate surface;

or

c2) Ink-jet printing a radiation curable varnish onto a second substrate surface, the second substrate surface being different from the substrate surface covered by the security feature and the first substrate surface;

and

d) curing the curable varnish to provide a protective coating covering the security feature surface, the first substrate surface and the second substrate surface facing away from the substrate;

wherein the varnish deposit on the second area is higher than the varnish deposit on the second substrate surface.

The manufacturing method as claimed and described herein enables the selective application of different varnish deposits onto different surfaces of a security document, including the front and back of the security document, in a single printing process, thereby providing a security document with improved chemical and physical resistance. The methods according to the prior art for applying protective varnishes on security documents are based on the exclusive use of flexographic printing or screen printing, and therefore the manufacture of security documents with variable coating thicknesses by said methods would require a large number of printing stations, resulting in complex, expensive and time-consuming manufacturing methods. Further, the manufacturing method claimed herein remains cost-effective, since the inventive manufacturing method described herein enables the selective application of large deposits of varnish on the first substrate surface adjacent to the edge of the security feature and on the first area of the security feature surface facing away from the substrate.

Drawings

Fig. 1-3, 4A-4C schematically illustrate a security document (100) according to the present invention comprising a substrate (110), a security feature (120) as described herein, and a protective coating (130A, 130B, 130C).

Fig. 5 schematically shows a top view of a security document (100') provided in step a) of the manufacturing method of the invention as claimed herein.

Detailed Description

Definition of

The following definitions are set forth to clarify the meaning of terms discussed in the specification and recited in the claims.

The indefinite articles "a" and "an", as used herein, mean one and greater than one, and do not necessarily limit their designated noun to unity.

As used herein, the term "about" means that the amount or value in question may be at or near the specified value. In general, the term "about" denoting a particular value is intended to mean a range within ± 5% of that value.

As one example, the phrase "about 100" means a range of 100 ± 5, i.e., a range from 95 to 105. Preferably, the range represented by the term "about" means a range within ± 3% of the value, more preferably ± 1%. In general, when the term "about" is used, it is contemplated that similar results or effects according to the present invention may be obtained within a range of ± 5% of the specified value.

As used herein, the term "and/or" means that all or only one of the set of elements may be present. For example, "a and/or B" means "only a, or only B, or both a and B. In the case of "a only", the term also covers the possibility that B is absent, i.e. "a only, but no B".

The term "comprising" as used herein is intended to be non-exclusive and open-ended. Thus, for example, a solution comprising compound a may comprise other compounds than a. However, the term "comprising" also encompasses the more limiting meanings of "consisting essentially of … …" and "consisting of … …" as specific embodiments thereof, such that, for example, "a solution comprising A, B and optionally C" may also consist (essentially) of a and B or (essentially) of A, B and C.

Where the present specification refers to "preferred" embodiments/features, combinations of these "preferred" embodiments/features should also be considered disclosed, as long as the particular combination of "preferred" embodiments/features is technically meaningful.

Surprisingly, a security document was found comprising:

a base material, a first metal layer and a second metal layer,

a security feature applied to or inserted into a portion of the substrate, wherein the security feature is selected from the group consisting of windowed security threads, security foils, security sheets, holograms and ink printed security features, having a security feature thickness t of at least about 5 μm (microns)_fAnd a security feature surface facing away from the substrate, the security feature surface being comprised of a first region adjacent an edge of the security feature and a second region not adjacent the edge of the security feature, and

protective coating, covering thereof

The surface of the security feature facing away from the substrate,

a first substrate surface adjacent an edge of the security feature, and

a second substrate surface different from the substrate surface covered by the security feature and the first substrate surface;

wherein

The protective coating covering the surface of the security feature facing away from the substrate and the surface of the first substrate is transparent, and

the protective coating covering the first area has a thickness t_b1，

The protective coating covering the second area has a thickness t_b2，

The protective coating covering the first substrate surface has a thickness t_cAnd is and

the protective coating covering the surface of the second substrate has a thickness t_a；

It is characterized in that

Thickness t_cGreater than thickness t_fThickness t_fGreater than thickness t_a；

Thickness t_b2Greater than thickness t_a；

And is

Thickness t_cGreater than thickness t_b1Thickness t_b1Greater than or equal to thickness t_b2；

Or thickness t_cIs equal to thickness t_b1Thickness t_b1Greater than thickness t_b2Exhibit improved resistance to physical and chemical damage from the environment when compared to prior art security documents, while maintaining the mechanical resistance required for such security documents.

In the security document according to the invention, the thickness t_cGreater than thickness t_fThickness t_fGreater than thickness t_a(t_c>t_f >t_a) Thickness t_b2Greater than thickness t_a(t_b2>t_a) And a thickness t_cGreater than thickness t_b1Thickness t_b1Greater than or equal to thickness t_b2(t_c>t_b1≥t_b2) Or thickness t_cIs equal to thickness t_b1Thickness t_b1Greater than thickness t_b2(t_c＝t_b1>t_b2)。

In other words, the invention relates to a security document comprising:

a base material, a first metal layer and a second metal layer,

a security feature applied to or inserted into a portion of the substrate, wherein the security feature is selected from the group consisting of windowed security threads, security foils, security sheets, holograms and ink printed security features, having a security feature thickness t of at least 5 μm (microns)_fAnd a security feature surface facing away from the substrate, the security feature surface being comprised of a first region adjacent an edge of the security feature and a second region not adjacent the edge of the security feature, and

protective coating, covering thereof

The surface of the security feature facing away from the substrate,

a first substrate surface adjacent an edge of the security feature, and

a second substrate surface different from the substrate surface covered by the security feature and the first substrate surface;

wherein

The protective coating covering the surface of the security feature facing away from the substrate and the surface of the first substrate is transparent, and

the protective coating covering the first area has a thickness t_b1，

The protective coating covering the second area has a thickness t_b2，

The protective coating covering the first substrate surface has a thickness t_cAnd is and

the protective coating covering the surface of the second substrate has a thickness t_a；

It is characterized in that

Thickness t_cGreater than thickness t_fThickness t_fGreater than thickness t_a；

Thickness t_b2Greater than thickness t_a(ii) a And a thickness t_cGreater than thickness t_b1Thickness t_b1Greater than or equal to thickness t_b2；

Or thickness t_cGreater than thickness t_fThickness t_fGreater than thickness t_a(ii) a Thickness t_b2Greater than thickness t_a(ii) a And a thickness t_cIs equal to thickness t_b1Thickness t_b1Greater than thickness t_b2。

Thus, a preferred embodiment according to the present invention relates to a security document as described herein, wherein the thickness t is_cGreater than thickness t_fThickness t_fGreater than thickness t_a(t_c>t_f >t_a) Thickness t_b2Greater than thickness t_a(t_b2>t_a) And a thickness t_cGreater than thickness t_b1Thickness t_b1Greater than or equal to thickness t_b2(t_c>t_b1≥t_b2). A further preferred embodiment according to the present invention relates to a security document as described herein, wherein the thickness t is_cGreater than thickness t_fThickness t_fGreater than thickness t_a(t_c>t_f >t_a) Thickness t_b2Greater than thickness t_a(t_b2>t_a) And a thickness t_cIs equal to thickness t_b1Thickness t_b1Greater than thickness t_b2(t_c＝t_b1>t_b2)。

As demonstrated, for example, by the results summarized in table 3, the security documents claimed herein exhibit a variable protective coating thickness on a surface thereof having a greater coating thickness (t) over a first substrate surface adjacent an edge of the security feature and a first region of the security feature surface facing away from the substrate than over the remaining surface of the security document_c，t_b1) Wherein the thickness t of the coating on the surface of the first substrate_cGreater than the thickness t of the security feature_fAnd is greater than or equal to the coating thickness t on the first region_b1In the chemical resistance test performed, the safety characteristics were not or hardly changed, thereby exhibiting excellent chemical resistance. The chemical resistance exhibited by the security document according to the invention is significantly higher than that obtained by a security document according to the prior art having a uniform protective coating of between about 2 μm and about 10 μm coating (see, for example, table 3: samples E1-E5 versus samples C2-C3 and C8-C11). Comparable chemical resistance can be observed with very large films having about 20 μm to 30 μm as observed for comparative examples C5, C6 and C13A security document of uniform coating thickness. However, as widely accepted in the security document world, a uniform protective coating thickness of more than 10 μm over the entire surface of a security document, such as a banknote, does not constitute a viable solution for technical reasons, such as the stiffness and cost of the coated security document. The security document according to the invention does not suffer from such problems due to the large coating thickness (t)_c，t_b1) Only on the first substrate surface adjacent to the edge of the security feature and on the first area of the security feature surface facing away from the substrate, i.e. on the very limited surface of the security document.

The protective coating covering the surface of the security feature facing away from the substrate and the surface of the first substrate is transparent, which is preferably colorless, so that the protective coating does not change the color of the security document. As used herein, if the coating is formed of a material having a specific thickness (t)_c，t_b1，t_b2) Is at most 5% higher in absolute value than the haze measured on the substrate covered by the coating, the specific thickness (t) is considered to be_c，t_b1，t_b2) The coating of (a) is transparent, wherein the haze measurement is carried out as described in ASTM D1003 (Standard test method for haze and light transmittance of clear plastics) using a DC 650 spectrophotometer (from DATACOLOR).

As used herein, the term "security document" refers to a document that has value making it potentially susceptible to counterfeiting or illegal copying, and which is typically protected from counterfeiting or fraud by at least one security feature. Typical examples of security documents include, without limitation, banknotes, contracts, tickets, checks, vouchers, tax stamps and tax labels, agreements, and the like, identification documents such as passports, identification cards, visas, bank cards, credit cards, transaction cards, access documents, tickets, and the like.

As used herein, the term "substrate" includes any security document substrate into which a windowed security foil may be inserted, or to which a security foil, security sheet, hologram or ink printed security feature may be applied. Security document substrates include, without limitation, paper or other fibrous materials such as cellulose, paper-containing materials, plastics and polymers, composites, and mixtures or combinations thereof. Typical paper, paper-like (paper-like) or other fibrous materials are made from a variety of fibers including, without limitation, abaca, cotton, flax, wood pulp, and blends thereof. As is well known to those skilled in the art, cotton and cotton/linen blends are preferred for banknotes, while wood pulp is typically used for non-banknote security documents. Typical examples of plastics and polymers include: polyolefins such as Polyethylene (PE) and polypropylene (PP), polyamides, polyesters such as poly (ethylene terephthalate) (PET), poly (1, 4-butylene terephthalate) (PBT), poly (ethylene 2, 6-naphthalate) (PEN), and polyvinyl chloride (PVC). Typical examples of composite materials include, without limitation, a multilayer structure or laminate of paper and at least one plastic or polymeric material, such as those described above. The substrate of the security document according to the present invention may be printed with any desired indicia, including any symbols, images and patterns, and/or may include one or more security features other than windowed security threads, security foils, security sheets, holograms and ink printed security features.

The security features described herein are applied to or inserted into a portion of a substrate (e.g., a security foil, a security sheet, a hologram, an ink-printed security feature). The security foils, security sheets and holograms described herein may be applied to a portion of a substrate by any known technique including, without limitation, applying a pressure sensitive adhesive to the surface of a security feature, applying a heat activated adhesive to the surface of a security feature or using a thermal transfer technique. When the substrate is paper, paper-like material or other fibrous material, the security feature may be inserted into a portion of the substrate by techniques commonly used in the paper industry. For example, the security features described herein may be fed into a cylinder mould papermaking machine (cylinder mould papermaking machine), a cylinder mould vat machine (cylinder vat machine) or other similar machine, resulting in the security features being partially embedded within the body of the finished substrate such that the security features have a surface facing away from the substrate. Furthermore, the ink-printed security features described herein may be obtained by applying a suitable security ink onto a substrate by inkjet printing, flexographic printing, gravure printing or screen printing, followed by curing the security ink by a suitable curing method.

As used herein, the terms "windowed security thread", "security foil", "security patch", "hologram" and "ink-printed security feature" refer to windowed security threads, security foils, security patches, holograms and ink-printed security features having a thickness of at least about 5 μm (microns). Preferably, the security features described herein are selected from windowed security threads, security foils, security patches and holograms.

As is well known to those skilled in the art, security threads, security foils and security sheets are security features comprising several layers, including functional layers such as optically variable layers, continuous or discontinuous metallized (i.e. demetallized) layers, magnetic layers, holographic layers, and exhibiting significant optically variable effects and/or dynamic color shifts that are easily identifiable. Due to the multilayer structure, the thickness of the security thread, security foil and security sheet is typically more than 5 μm (micrometer).

Security threads are most often classified as public (i.e., first security level) security features, i.e., security features that can be identified without any technical knowledge or tools by laypersons. The security thread provides a first security level of optical effect using a color-changing ink, hologram or lenticular structure, which can be verified in reflected light by tilting the object to observe "motion" in the optical effect. The security thread may integrate further information such as simple text or numerical values. Security threads are elongate security features that are inserted into security document substrates (e.g., banknote paper, standard tissue paper, and various combinations of cotton and synthetic fibers, banknote layered substrates, paper passport visas) during their manufacture. The security threads may be incorporated into the security substrate such that they are not visible in reflected light (so-called embedded threads) or appear and disappear periodically on one side of the security substrate (so-called windowed threads). As known to those skilled in the art and as used herein, "windowed security thread" refers to a security thread that is inserted into a substrate such that a portion of one of the thread surfaces is onVisible at different intervals on one surface of the substrate (i.e. the surface of the security feature facing away from the substrate). Preferably, the windowed security thread is selected from the group consisting of a metallised thread, a partially demetallised thread, a holographic thread, a lenticular thread and a colour-changing thread. Typically, the dimension of the security thread in the longitudinal direction (i.e. the length) is more than twice its dimension in the transverse direction (i.e. the width). The security thread typically has a width (i.e., dimension in the transverse direction) between about 1mm and about 10mm and a thickness (t) between about 10 and about 45 μm (micrometers)_f)。

Security foils are elongated security features that are wider than the line width, thereby providing more space for individual designs. The security patch is smaller than the security foil, i.e. the dimension (i.e. length) of the security patch in the longitudinal direction is significantly smaller than the dimension of the security foil in the longitudinal direction. Examples of security foils and security sheets include, without limitation, metallized foils, partially demetallized foils, metallized patches, partially demetallized sheets, holographic foils, holographic sheets, lenticular foils, lenticular sheets, color shifting foils and color shifting sheets. The security foils and security sheets typically have a thickness (t) between about 5 and about 45 μm (micrometers)_f). The security foil and the security sheet are applied to the security document substrate by gluing or hot embossing and have a surface facing away from the security document substrate.

Holograms are diffractive optically variable security features which may be integrated in security threads, security foils, security sheets, or applied directly to a security document substrate by gluing or hot embossing, for example as part of a window of a security document such as a banknote. The hologram is a multilayer structure comprising a layer into which a holographic relief pattern is embossed, a reflective layer providing a hologram with high diffraction efficiency. If the hologram is applied directly to the substrate, the hologram further comprises a protective layer which ensures that the reflective layer is not damaged by the adhesive layer required to apply the hologram to the substrate. The reflective layer is typically composed of a vacuum deposited metal, which may be aluminum or another metal (e.g., gold or chromium), or it may be composed of a transparent substance, such as titanium dioxide (TiO)₂) Or zinc sulfide (ZnS). In the latter case, the hologram will be semi-transparent and derived from the high refractive index of the oxide or sulfideIt is highly reflective. To obtain a see-through hologram, the metallic reflective layer of the multilayer structure is selectively demetallised by methods known to those skilled in the art. The see-through hologram exhibits a reduced reflectivity due to the removal of metal and has a see-through characteristic in that if the material is placed on a printed or photographic substance, the place where the metal is removed can be seen. As used herein, a hologram refers to a hologram having a thickness of between about 5 to about 15 μm (micrometers).

As used herein, the term "ink-printed security feature" refers to a security feature having a thickness of at least about 5 μm (micrometers) obtained by printing a security ink on a security document by inkjet, flexographic, gravure or screen printing, the security ink comprising one or more security materials selected from the group consisting of magnetic pigments, UV-absorbing pigments, IR-absorbing pigments, optically variable pigments, light-polarizing pigments, photoluminescent pigments, electrically conductive pigments, surface-enhanced raman spectroscopy particles and plasmon resonance particles, such as the plate-like transition metal particles described by WO2011064162a2, WO2013186167a2 and WO2014041121a 1. European patent application No. EP20171031.6 discloses an example of an ink-printed security feature obtained with a security ink containing plasmon resonance particles.

The security features described herein have a security feature thickness t of at least 5 μm (micrometers)_fWhich is determined, for example, by cross-sectional observation on a microscope. Typically, the windowed security thread has a thickness t of between about 10 and about 45 μm_fThe security foil and the security sheet have a thickness t of between about 5 and about 45 μm_fThe hologram has a thickness t between about 5 to about 15 μm_fAnd the ink printed security feature has a thickness t between about 5 to about 50 μm_f。

As shown in fig. 5, which shows a top view of an example of a security document (100 ') provided in step a) of the manufacturing method claimed herein, the security document (100') comprises a substrate (110) to which a security feature (120) is applied or on which the security feature (120) is inserted, the security feature (120) applied or inserted into a portion of the substrate (110) having a surface facing away from the substrate (110)Noodle (120)_b). The surface (120) of the security feature (120) facing away from the substrate (110)_b) By a first region (120) adjacent to an edge of the security feature (120)_b1A dot pattern) and a second area (120) not adjacent to the edge of the security feature (120)_b2-a grid pattern). A first region (120) adjacent to an edge of the security feature (120)_b1Dot pattern) will have a thickness t_b1Covers a second area (120) not adjacent to the edge of the security feature (120)_b2Grid pattern) will have a thickness t_b2Is covered by a transparent protective coating (130B). As used herein, "first region adjacent to an edge of a security feature" refers to a region of the surface of the security feature facing away from the substrate, which is bounded by the edge of the security feature, and has a width w_b1Between about 0.5 and about 5mm, preferably between about 1 and about 4mm, and more preferably about 2mm, wherein the width w_b1Not necessarily constant along the entire first area. In fig. 5, a first area adjacent to the edge of the security feature corresponds to the surface 120 having a dot pattern design_b1. As used herein, "second region not adjacent to an edge of the security feature" refers to a region of the surface of the security feature facing away from the substrate that is complementary to the first region, i.e., a region of the surface of the security feature facing away from the substrate that is different from the first region. In fig. 5, a second region not adjacent to the edge of the security feature corresponds to the surface 120 having a grid pattern design_b2。

As used herein, "first substrate surface adjacent to an edge of a security feature" refers to the substrate surface at the edge of the security feature, which has a width w_cBetween about 0.5 and 5mm, preferably between about 1 and 4mm, and more preferably between about 2 and 3mm, wherein the width w_cNot necessarily constant along the entire first substrate surface. Thus, the transparent protective coating covering the surface of the security feature facing away from the substrate and the first substrate surface adjacent the edge of the security feature is a continuous coating, i.e., there are no uncoated areas on the surface of the security document that are exposed to the external environment. In FIG. 5, the edges with the security featureThe edge-adjacent first substrate surface corresponds to the unpatterned surface 110_cAnd a second substrate surface, different from the substrate surface covered by the security feature and the first substrate surface, corresponds to a horizontal strip patterned surface 110_a。

The security document according to the present invention may comprise on one of its sides an uncoated area of between about 5 and about 15% of the substrate surface, wherein the percentage is based on the total surface of the security document. Preferably, the uncoated region is present on at least one edge or corner of the substrate. The uncoated areas may be used, for example, to number security documents. If the security document is a banknote, the uncoated area may additionally be used to absorb a colouring (non-discolouring) ink for protecting the banknote from theft and robbery, as described in international patent application publication No. WO2013127715a 2. The uncoated region may be located on the same side of the security document as the security feature or on the opposite side of the security document.

Preferably, the security document according to the invention does not comprise uncoated areas, i.e. the protective coating completely covers both sides, i.e. the front and back, of the security document. As shown in fig. 4A and 4B, in this case, the second substrate surface that is not adjacent to the edge of the security document comprises the surface of the security document substrate on both sides of the security document except for the substrate surface covered by the security feature (120) and the first substrate surface.

The thickness t of the protective coating covering the surface of the second substrate in order to maintain a low production cost without affecting the mechanical properties of the security document_aLess than about 5 μm, preferably between about 1 and 3 μm.

As used herein, a first thickness being greater than a second thickness means that the first thickness is at least about 10% greater than the second thickness, preferably at least about 50% greater, more preferably at least about 100% greater, and even more preferably at least about 200% greater, where both thicknesses are determined by cross-sectional observation on a microscope. Thus, if a security feature selected from the group consisting of windowed security threads, security foils, security sheets, holograms and ink-printed security features has a thickness t of about 10 μm_fThen the thickness t of the transparent protective coating covering the first substrate surface_cIs at least11 μm, preferably at least 15 μm, more preferably at least about 20 μm, and more preferably at least about 30 μm. Further, if, for example, the thickness t of the protective coating covering the surface of the second substrate is t_aAbout 2 μm, the thickness t of the transparent protective coating covering the second region of the security feature_b2Is at least about 2.2 μm, preferably at least about 3 μm, more preferably at least about 4 μm, and even more preferably at least about 6 μm, for example about 7 μm.

Preferably, the thickness t of the transparent protective coating covering the surface of the first substrate_cThickness t of security feature_fThe ratio of (A) to (B) is comprised between about 1.1 and about 4, more preferably between about 1.5 and about 3, and more preferably between about 2 and about 3. A security document is characterized in that the thickness of such a protective coating exhibits excellent chemical resistance.

A preferred embodiment according to the present invention relates to a security document as described herein, wherein the thickness t of the transparent protective coating covering the first substrate surface_cGreater than or equal to the thickness t of the security feature_fAnd a thickness t of the transparent protective coating covering the second region of the security feature_b2Sum of (t)_c≥t_f +t_b2)。

A further embodiment according to the present invention relates to a security document as described herein, wherein the portion of the substrate to which the security feature is applied is a transparent polymer. By applying security foils, security sheets, holograms or ink printed security features to a transparent polymeric substrate, security documents can be equipped with a secure transparent window, one of the most advanced security features, which is easy to identify and extremely difficult to counterfeit, since window copy replication results in a black window and the manufacturing process is limited to security document manufacture and is not suitable for commercial printing and paper technology. In order to avoid compromising the properties of the security feature carried by such a security document, the surface of the transparent polymer portion opposite the surface of the transparent polymer portion to which the security feature is applied should not be covered by a protective coating.

In embodiments according to the invention, a transparent protective coating covering the surface of the security feature facing away from the substrate and the surface of the first substrate and a transparent protective coating covering the surface of the second substrateThe protective coating layers of (a) are each obtained from different curable varnishes, i.e. the transparent protective coating covering the surface of the security feature facing away from the substrate and the surface of the first substrate and the protective coating covering the surface of the second substrate are obtained from two different curable varnishes. Preferably, the transparent protective coating covering the surface of the security feature facing away from the substrate and the surface of the first substrate consists of a single layer obtained from the first curable varnish. The single clear coating extends or covers the entire security feature surface facing away from the substrate and the entire first substrate surface and is present with a variable thickness, having a coating thickness t on the first substrate surface_cGreater than the thickness t of the security feature_fAnd is greater than or equal to the coating thickness t on the first region of the security feature_b1Preferably with a coating thickness t on the surface of the first substrate_cGreater than or equal to the thickness t of the security feature_fAnd a coating thickness t over a second region of the security feature_b2Provides improved chemical resistance to the security document according to the invention when compared to security documents according to the prior art having a constant coating. Advantageously, the protective coating covering the second substrate surface is a matte finish and/or the transparent protective coating covering the security feature surface facing away from the substrate and the first substrate surface is a flash finish. In other words, the protective coating covering the second substrate surface is obtained from a first curable varnish (e.g., the radiation curable varnish described in international patent application publication No. WO2014067715a1, C1-C10, E1, E2) which, after curing, provides a matte protective coating and/or the transparent protective coating covering the security feature surface facing away from the substrate and the first substrate surface is obtained from a second curable varnish (e.g., a curable varnish according to table 1 below) which, after curing, provides a sparkling transparent protective coating. To facilitate storage, stacking and gripping of security documents, in particular banknotes, the protective coating covering the surface of the second substrate is preferably a matte lacquer, which provides better grip. In addition, the matt varnish has the advantage of retaining the customary perception of the security document by the user by touch and produces much less reflection than gloss varnish, so that the security document can be machine-inspected with the optical sensors usually usedAnd authentication. Since matte protective lacquers, and in particular thick matte lacquers, impair the optical properties of security features such as windowed security threads, security foils, security sheets, holograms and ink-printed security features by reducing their brightness and blurring their appearance, such matte lacquers should not be used to protect the surface of the security feature facing away from the substrate and the surface of the first substrate adjacent to the edge of the security feature. Thus, the transparent protective coating covering the surface of the security feature facing away from the substrate and the first substrate surface adjacent the edge of the security feature is preferably a flash lacquer, which is free of components having a light scattering effect, such as fillers. The flash paint is conspicuous and draws layman attention to the security feature covered by the flash paint, thereby helping inexperienced users to easily find the security feature on the security document.

A further preferred embodiment according to the present invention relates to a security document as described herein, wherein the transparent protective coating covering the surface of the security feature facing away from the substrate and the surface of the first substrate comprises two different layers, and one of the two different layers has the same thickness t as the transparent protective coating covering the surface of the second substrate_aAnd is obtained from the same curable varnish as the transparent protective coating covering the surface of the second substrate.

In another preferred embodiment according to the present invention, the protective coating covering the surface of the security feature facing away from the substrate, the first substrate surface adjacent to the edge of the security feature and the second substrate surface different from the substrate surface covered by the security feature and the first substrate surface is comprised of a bottom bracket. In this case, the protective coatings on the different surfaces of the security document are transparent and are obtained from the same curable varnish, preferably a radiation curable varnish and more preferably a UV-curable varnish.

Preferably, the inventive security document claimed herein is obtained by a manufacturing method comprising the steps of:

a) providing a security document comprising:

a base material, a first metal layer and a second metal layer,

a security feature applied to or inserted into a portion of the substrate,

wherein the security feature is selected from windowed security threads, security foils, security sheets, holograms and ink-printed security features, having a security feature thickness t of at least 5 μm (micrometres)_fAnd a security feature surface facing away from the substrate, the security feature surface being comprised of a first region adjacent an edge of the security feature and a second region not adjacent the edge of the security feature;

b) inkjet printing a radiation curable varnish onto a surface of the security feature facing away from the substrate and a first substrate surface adjacent an edge of the security feature, wherein the varnish deposit on the first substrate surface is equal to or higher than the varnish deposit on a first region adjacent the edge of the security feature and the varnish deposit on the first region is equal to or higher than, preferably higher than, the varnish deposit on a second region;

and

c1) printing a curable varnish by offset or flexographic printing on a second substrate surface, the second substrate surface being different from the substrate surface covered by the security feature and the first substrate surface, and optionally on the security feature surface facing away from the substrate and the first substrate surface;

or

c2) Inkjet printing a radiation curable varnish on a second substrate surface, the second substrate surface being different from the substrate surface covered by the security feature and the first substrate surface;

and

d) curing the curable varnish to provide a protective coating covering the surface of the security feature facing away from the substrate, the surface of the first substrate, and the surface of the second substrate;

wherein the varnish deposit on the second area is higher than the varnish deposit on the second substrate surface.

This is common knowledge of the person skilled in the art of printing technology in view of the printing process, which includes the printing technology (e.g. inkjet, offset, flexographic printing) and the parametric characteristics of that particular technology, such as ink properties (e.g. viscosity and surface tension) and process variables (e.g. the composition of the anilox impression)Resolution (dpi), blanket hardness, mesh and depth) to select the varnish deposit, followed by a curing step d) of thickness t of the transparent protective coating covering the surface of the first substrate_cGreater than the thickness t of the security feature_fThickness t_fIs greater than the thickness t of the protective coating covering the surface of the second substrate_a(t_c>t_f>t_a) Thickness t of the transparent protective coating covering the second area of the security feature_b2Is greater than the thickness t of the protective coating covering the surface of the second substrate_a(t_b2>t_a) And a thickness t of the transparent protective coating covering the surface of the first substrate_cGreater than the thickness t of the transparent protective coating covering the first area of the security feature_b1Thickness t_b1Greater than or equal to the thickness t of the transparent protective coating covering the second area of the security feature_b2(t_c>t_b1≥t_b2) Or the thickness t of the transparent protective coating covering the surface of the first substrate_cEqual to the thickness t of the transparent protective coating covering the first area of the security feature_b1Thickness t_b1Greater than the thickness t of the transparent protective coating covering the second area of the security feature_b2(t_c＝t_b1>t_b2)。

As is well known in the art, the term "varnish deposit" (g/m)²) Is the m of the surface²The amount of varnish applied in grams. As used herein, the first varnish deposit being higher than the second varnish deposit means that the first varnish deposit is at least about 10% higher, preferably at least about 50% higher, more preferably at least about 100% higher, and even more preferably at least about 200% higher than the second varnish deposit.

According to a further aspect the present invention relates to a method of manufacturing a security document as claimed herein, comprising the steps of:

a) providing a security document comprising:

a base material, a first metal layer and a second metal layer,

a security feature applied to or inserted into a portion of the substrate,

wherein the security feature is selected from a windowSecurity thread, security foil, security sheet, hologram and ink printed security feature having a security feature thickness t of at least 5 μm (micrometre)_fAnd a security feature surface facing away from the substrate, the security feature surface being comprised of a first region adjacent an edge of the security feature and a second region not adjacent the edge of the security feature;

b) inkjet printing a radiation curable varnish onto a surface of the security feature facing away from the substrate and a first substrate surface adjacent an edge of the security feature, wherein the varnish deposit on the first substrate surface is greater than or higher than the varnish deposit on a first region adjacent the edge of the security feature and the varnish deposit on the first region is equal to or higher than, preferably higher than, the varnish deposit on a second region;

and

c1) printing a curable varnish by offset or flexographic printing on a second substrate surface, the second substrate surface being different from the substrate surface covered by the security feature and the first substrate surface, and optionally on the security feature surface facing away from the substrate and the first substrate surface;

or

c2) Inkjet printing a radiation curable varnish on a second substrate surface, the second substrate surface being different from the substrate surface covered by the security feature and the first substrate surface;

and

d) curing the curable varnish to provide a protective coating covering the security feature surface, the first substrate surface, and the second substrate surface, which are facing away from the substrate;

wherein the varnish deposit on the second area is higher than the varnish deposit on the second substrate surface.

The security document (100') provided by step a) of the manufacturing method claimed herein is illustrated by fig. 5 showing a top view of such a security document. The security document (100') comprises a substrate (110) to which a security feature (120) is applied or onto which the security feature (120) is inserted by methods known in the art, wherein the security feature (120) has a surface (120) facing away from the substrate (110)_b) Surface (120)_b) By a first region adjacent to an edge of the security feature (120) ((120_b1A dot pattern) and a second area (120) not adjacent to the edge of the security feature (120)_b2-a grid pattern). A first substrate surface (110) adjacent to an edge of the security feature (120)_c) And a second substrate surface (110)_a-a horizontal stripe pattern) of the second substrate surface (110)_a) Different from the substrate surface covered by the security feature (120) and the first substrate surface (110)_c). Different varnish deposits will be printed on different surfaces (110) of the substrate (110) and the security feature (120) by performing steps b) and c1), or steps b) and c2), of the manufacturing method claimed herein_a、110_c、120_b1、120_b2) The above.

The term "cure" or "curability" is meant to include the process of drying or solidifying, reacting or polymerizing the applied varnish in such a way that it can no longer be removed from the surface to which it is applied. Examples of curing mechanisms include physical curing (e.g., removal of volatile components such as solvents by heating, permeation) and chemical curing (e.g., polymerization, oxidation), or a combination of physical and chemical curing (e.g., removal of volatile components followed by polymerization).

As used herein, the term "curable varnish" encompasses oxidation-curable varnishes, heat-curable varnishes, radiation-curable varnishes or combinations thereof (e.g., varnishes having a composition similar to radiation-curable varnishes, but including volatile moieties comprised of water or comprised of solvents, which are cured by evaporation of the volatile moieties using a hot air or IR dryer, followed by UV curing or EB curing to complete the curing process), which are suitable for printing by inkjet, offset or flexographic printing.

The oxidation-curable varnish is cured by oxidation in the presence of oxygen, in particular in the presence of atmospheric oxygen. During curing, oxygen combines with one or more components of the varnish, thereby converting the varnish into a solid state. This process may be facilitated by the use of a drying agent (also referred to in the art as a catalyst, drying agent (drying agent) or moisture absorber (desiccant)), such as inorganic or organic salts of metals, metal soaps of organic acids, metal complexes and metal complex salts, optionally with the application of a heat treatment, which is preferably present in an amount of about 0.01 to about 10 wt-%, more preferably in an amount of about 0.1 to about 5 wt-%, weight percentages being based on the total weight of the oxidatively curable varnish. The one or more driers include, but are not limited to, multivalent salts containing cobalt, calcium, copper, zinc, iron, zirconium, manganese, barium, zinc, strontium, lithium, vanadium, and potassium as cations, and halides, nitrates, sulfates, carboxylates such as acetate, ethylhexanoate, octanoate, and naphthenate or acetylacetonate as anions. Preferably, the one or more drying agents are selected from the group consisting of ethylhexanoates or octanoates of manganese, cobalt, calcium, strontium, zirconium, zinc and mixtures thereof.

The oxidation curable varnish further comprises one or more polymers comprising polymers of unsaturated fatty acid residues, saturated fatty acid residues, and mixtures thereof, as is generally known in the art. The one or more polymers are present in an amount of about 10 to about 90 wt-%, weight percents based on the total weight of the oxidation-curable varnish. Preferably, the one or more polymers include unsaturated fatty acid residues to ensure air drying performance. However, the one or more polymers may also include saturated fatty acid residues. The one or more polymers may be selected from the group consisting of alkyd resins, vinyl polymers, polyurethane resins, hyperbranched resins, rosin-modified maleic resins, rosin-modified phenolic resins, rosin esters, petroleum resin-modified alkyd resins, alkyd resin-modified rosin/phenolic resins, alkyd resin-modified rosin esters, acrylic-modified rosin/phenolic resins, acrylic-modified rosin esters, polyurethane-modified rosin/phenolic resins, polyurethane-modified rosin esters, polyurethane-modified alkyd resins, epoxy-modified rosin/phenolic resins, epoxy-modified alkyd resins, terpene resins, nitrocellulose resins, polyolefins, polyamides, acrylic resins, and combinations or mixtures thereof. Polymers and resins are used interchangeably herein.

The saturated and unsaturated fatty acid compounds may be obtained from natural and/or artificial sources. Natural sources include animal sources and/orIs of plant origin. Animal sources may include animal fat, milk fat, fish oil, lard, liver fat, tuna fish oil, sperm whale oil and/or tallow and wax. The vegetable source may comprise waxes and/or oils, for example vegetable oils and/or non-vegetable oils. Examples of vegetable oils include, without limitation, bitter gourd, borage, calendula, canola, castor, tung oil (china wood), coconut, conifer seed, corn, cottonseed, dehydrated castor, linseed, grape seed, jacaranda seed, linseed oil, palm kernel, peanut, pomegranate seed, rapeseed (rapeseed), safflower, loofah, soybean (bean), sunflower, tall (tall), tung and malt. Artificial sources include synthetic waxes (e.g., microcrystals and/or paraffin waxes), distilled tall oil, and/or chemical or biochemical synthetic methods. Suitable fatty acids also include (Z) -hexadec-9-enoic acid [ palmitoleic acid ]](C₁₆H₃₀O₂) (Z) -Octadeca-9-enoic acid [ oleic acid ]](C₁₈H₃₄O₂) (9Z,11E,13E) -octadecane-9, 11, 13-trienoic acid [ a-eleostearic acid ]](C₁₈H₃₀O₂) Octadecatriene-4-keto acid (licanic acid), (9Z,12Z) -octadeca-9, 12-dienoic acid [ linoleic acid ]](C₁₈H₃₂O₂) (5Z,8Z,11Z,14Z) -eicosa-5, 8,11, 14-tetraenoic acid [ arachidonic acid ]](C₂₀H₃₂O₂) 12-hydroxy- (9Z) -octadec-9-enoic acid [ ricinoleic acid ]](C₁₈H₃₄O₃) (Z) -docosahexen-13-enoic acid [ erucic acid](C₂₂H₄₂O₃) (Z) -eicosa-9-enoic acid [ gadoleic acid ]](C₂₀H₃₈O₂) (7Z,10Z,13Z,16Z,19Z) -docosac-7, 10,13,16, 19-pentaenoic acid [ clupanodonic acid [ -clupanodonic acid]And mixtures thereof.

Further examples of suitable fatty acids are ethylenically unsaturated conjugated or non-conjugated C₂-C₂₄Carboxylic acids such as myristoleic acid, palmitoleic acid, arachidonic acid, erucic acid, gadoleic acid (gadolenic acid), clupanodonic acid (clupanodonic acid), oleic acid, ricinoleic acid, linoleic acid, linolenic acid, octadecatrien-4-keto acid, tetracosahexanoic acid (nisinic acid) and eleostearic acid or mixtures thereof. These fatty acids are generally used in the form of fatty acid mixtures derived from natural or synthetic oils.

The oxidatively curable varnish may further comprise one or more antioxidants, such as those known to those skilled in the art. Suitable antioxidants include, without limitation, alkyl phenols, hindered alkyl phenols, alkyl thiomethylphenols, eugenol, secondary amines, thioethers, phosphites, phosphonites, dithiocarbamates, gallates, malonates, propionates, acetates and other esters, carboxamides, hydroquinones, ascorbic acid, triazines, benzyl compounds, and tocopherols and similar terpenes. Such antioxidants are commercially available from sources such as those disclosed in international patent application publication No. WO02100960a 1. Hindered alkylphenols are phenols having at least one or two alkyl groups ortho to the phenolic hydroxyl group. One, preferably both, alkyl groups ortho to the phenolic hydroxyl group are preferably secondary or tertiary alkyl groups, more preferably tertiary alkyl groups, especially tertiary butyl, tertiary amyl or 1,1,3, 3-tetramethylbutyl. Preferred antioxidants are hindered alkylphenols, in particular 2-tert-butyl-hydroquinone, 2, 5-di-tert-butyl-hydroquinone, 2-tert-butyl-p-cresol and 2, 6-di-tert-butyl-p-cresol. When present, the one or more antioxidants are present in an amount of about 0.05 to about 3 weight-%, weight percents based on the total weight of the oxidation-curable varnish.

The oxidation-curable varnish described herein may further comprise one or more waxes, preferably selected from the group consisting of synthetic waxes, petroleum waxes and natural waxes. Preferably, the one or more waxes are selected from the group consisting of microcrystalline waxes, paraffin waxes, polyethylene waxes, fluorocarbon waxes, polytetrafluoroethylene waxes, Fischer-Tropsch waxes, silicone oils, beeswax, candelilla wax (candelilla wax), montan wax, carnauba wax and mixtures thereof. When present, the one or more waxes are preferably present in an amount of about 0.1 to about 15 wt-%, weight percents based on the total weight of the oxidation-curable varnish.

The oxidation curable varnish may further include one or more fillers and/or extenders preferably selected from the group consisting of carbon fibers, talc, mica (e.g., muscovite), wollastonite, calcined clay, china clay, kaolin, carbonates (e.g., calcium carbonate, sodium aluminum carbonate), silicates (e.g., magnesium silicate, aluminum silicate), sulfates (e.g., magnesium sulfate, barium sulfate), titanates (e.g., potassium titanate), hydrated alumina, silica, fumed silica, montmorillonite, graphite, anatase, rutile, bentonite, vermiculite, zinc white, zinc sulfide, wood flour, quartz flour, natural fibers, synthetic fibers, and combinations thereof. When present, the one or more fillers and/or extenders are preferably present in an amount of about 0.1 to about 40 weight-%, weight percents being based on the total weight of the oxidation curable varnish.

As used herein, the term "heat-curable varnish" includes any water-borne varnish and any solvent-borne varnish that can be cured by cold air, hot air, infrared light, or a combination thereof. Typically, the heat-curable varnish comprises 50-65-wt% of water, organic solvent or and mixtures, which evaporate during curing.

Typically, the heat-curable varnish includes components including, without limitation, resins such as polyester resins, polyether resins, vinyl chloride polymers and vinyl chloride-based copolymers, nitrocellulose resins, cellulose acetobutyrate or levulinate resins, maleic resins, polyamides, polyolefins, polyurethane resins, functionalized polyurethane resins (e.g., carboxylated polyurethane resins), polyurethane alkyd resins, polyurethane- (meth) acrylate resins, polyurethane- (meth) acrylic resins, styrene (meth) acrylate resins, or mixtures thereof. The term "(meth) acrylate" or "(meth) acrylic acid" refers to an acrylate and the corresponding methacrylate, or to acrylic acid and the corresponding methacrylic acid.

As used herein, the term "aqueous varnish" refers to an aqueous dispersion comprising components including, without limitation, resins having ester linkages (e.g., polyester resins, polyether resins), polyurethane resins, polyurethane alkyds, polyurethane resins (e.g., carboxylated polyurethane resins), polyurethane alkyds, polyurethane-acrylate resins, urethane-acrylic resins, polyether polyurethane resins, styrene acrylate resins, or mixtures thereof.

As used herein, the term "solvent-based varnish" refers to a varnish whose liquid medium or carrier consists essentially of one or more organic solvents. Examples of such solvents include, without limitation, alcohols (e.g., methanol, ethanol, isopropanol, n-propanol, ethoxypropanol, n-butanol, sec-butanol, tert-butanol, isobutanol, 2-ethylhexanol, and mixtures thereof); polyols (e.g., glycerol, 1, 5-pentanediol, 1,2, 6-hexanetriol, and mixtures thereof); esters (e.g., ethyl acetate, n-propyl acetate, n-butyl acetate, and mixtures thereof); carbonates (e.g., dimethyl carbonate, diethyl carbonate, di-n-butyl carbonate, 1, 2-ethylene carbonate, 1, 2-propylene carbonate, 1, 3-propylene carbonate, and mixtures thereof); aromatic solvents (e.g., toluene, xylene, and mixtures thereof); ketones and ketoalcohols (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol, and mixtures thereof); amides (e.g., dimethylformamide, dimethylacetamide, and mixtures thereof); aliphatic or cycloaliphatic hydrocarbons; chlorinated hydrocarbons (e.g., dichloromethane); nitrogen-containing heterocyclic compounds (e.g., N-methyl-2-pyrrolidone, 1, 3-dimethyl-2-imidazolidinone, and mixtures thereof); ethers (e.g., diethyl ether, tetrahydrofuran, dioxane, and mixtures thereof); alkyl ethers of polyhydric alcohols (e.g., 2-methoxyethanol, 1-methoxypropan-2-ol, and mixtures thereof); alkylene glycols, alkylene thioglycols, polyalkylene glycols or polyalkylene thioglycols (e.g., ethylene glycol, polyethylene glycols (e.g., diethylene glycol, triethylene glycol, tetraethylene glycol), propylene glycol, polypropylene glycols (e.g., dipropylene glycol, tripropylene glycol), butylene glycol, thiodiglycol, hexylene glycol, and mixtures thereof); nitriles (e.g., acetonitrile, propionitrile, and mixtures thereof), and sulfur-containing compounds (e.g., dimethyl sulfoxide, sulfolane, and mixtures thereof). Preferably, the one or more solvents are selected from the group consisting of alcohols, esters and mixtures thereof.

In a preferred embodiment, the curable varnish used in the present invention is a radiation curable varnish. As is well known to those skilled in the art, the term "radiation curable varnish" encompasses varnishes which can be cured by UV-visible radiation (hereinafter UV-Vis-curable) or by electron beam radiation (hereinafter EB). Radiation curing advantageously leads to a very fast curing process and thus greatly reduces the manufacturing time of a security document comprising a transparent protective coating obtained from a radiation curable varnish. Radiation curable compositions are known in the art and can be queried in standard textbooks such as the series "Chemistry & Technology of UV & EB Formulation for Coatings, Inks & Paints", 1997 + 1998, volume 7, by John Wiley & Sons, in combination with SITA Technology Limited.

Preferably, the radiation curable varnish is a UV-visible light curable varnish including monomers (i.e., prepolymers) and oligomers (i.e., prepolymers) selected from the group consisting of radical curable compounds and cation curable compounds and mixtures of radical curable compounds and cation curable compounds.

The free radical curable compounds cure by a free radical mechanism that includes the formation of a coating by energy activation of one or more photoinitiators that release free radicals followed by initiation of polymerization. Preferably, the radically curable compound is selected from (meth) acrylates, preferably from epoxy (meth) acrylates, (meth) acrylated oils, polyester and polyether (meth) acrylates, aliphatic or aromatic urethane (meth) acrylates, silicone (meth) acrylates, acrylic (meth) acrylates and mixtures thereof. The term "(meth) acrylate" refers to both acrylates and the corresponding methacrylates.

Cationic curable compounds cure by a cationic mechanism that includes the formation of a coating by energy activation of one or more photoinitiators that release a cationic species, such as an acid, followed by initiation of polymerization of the compound. Preferably, the one or more cationically curable compounds are selected from the group consisting of vinyl ethers, propenyl ethers, cyclic ethers such as epoxides, oxetanes and tetrahydrofurans, lactones, cyclic thioethers, vinyl thioethers, propenyl thioethers, hydroxyl containing compounds and mixtures thereof, preferably the cationically curable compounds are selected from the group consisting of vinyl ethers, propenyl ethers, cyclic ethers such as epoxides, oxetanes and tetrahydrofurans, lactones and mixtures thereof.

UV-Vis curing of monomers, oligomers or prepolymers requires the presence of one or more photoinitiators and can be achieved in a variety of ways. As known to those skilled in the art, the one or more photoinitiators are selected according to their absorption spectrum and the emission spectrum of the radiation source is selected to be suitable. Depending on the monomers, oligomers or prepolymers used for the preparation of the radiation-curable varnishes, different photoinitiators can be used.

Suitable examples of cationic photoinitiators are known to those skilled in the art and include, without limitation, onium salts, such as organoiodonium salts (e.g., diaryliodonium salts), oxonium salts (e.g., triaryloxonium salts), and sulfonium salts (e.g., triarylsulfonium salts).

Suitable examples of free radical photoinitiators are known to those skilled in the art and include, without limitation, acetophenone, benzophenone, alpha-amino ketones, alpha-hydroxy ketones, phosphine oxides and phosphine oxide derivatives, and benzyl dimethyl ketal. Other examples of useful Photoinitiators can be found in standard textbooks such as "Chemistry & Technology of UV & EB Formulation for Coatings, Inks & Paints", volume III, "photonics for Free radial catalysis and analytical Polymerization", 2 nd edition, J.V.Crivello & K.Dietliker, edited by G.Bradley and published by John Wiley & Sons in 1998 in conjunction with SITA Technology Limited.

Inkjet other printing includes Continuous Inkjet (CIJ) printing and Drop On Demand (DOD) inkjet printing.

Among the manufacturing methods described herein, DOD inkjet printing is preferred. Drop On Demand (DOD) printing is a non-contact printing process in which drops are only produced when required for printing, and are typically produced by a jetting mechanism rather than by destabilizing the jet. DOD printing is divided into piezoelectric pulses, thermal ejection, and valve ejection, depending on the mechanism used to generate the drops in the printhead. In order to be suitable for DOD inkjet printing, the radiation curable varnish must have a low viscosity of less than about 20cP at the jetting temperature and a surface tension of less than about 45N/m.

Offset printing processes include indirect methods in which a curable varnish is transferred from a plate onto a blanket cylinder and then the curable varnish is transferred onto a substrate. Thus, the blanket cylinder is painted from the printing plate. Offset printing utilizes the difference in surface energy between the image and non-image areas of the plate. The image areas are oleophilic, while the non-image areas are hydrophilic. Therefore, the oil-based curable varnish used in this method tends to adhere to the image area of the printing plate and repel from the non-image area of the printing plate. Wet offset printing is typically performed by: both a fountain solution (also referred to as dampening liquid) and a lipophilic curable varnish are supplied to the printing plate to allow the image areas to preferentially receive the curable varnish and the non-image areas to preferentially receive the fountain solution, and then the curable varnish deposited on the image areas is transferred onto the substrate.

For use in offset printing, the curable varnish is applied at 40 ℃ for 1000s^-1The viscosity of (B) must be in the range of about 2.5 to about 25Pa s, as measured on a Haake Roto-Visco RV1 with a 2cm 0.5 ° cone.

Flexographic printing preferably uses units having a doctor blade, preferably a chambered doctor blade, an anilox roller and a plate cylinder. The anilox roller advantageously has small cells, the volume and/or density of which determines the speed of application of the curable varnish. The doctor blade is pressed against the anilox roller and simultaneously scrapes off the remaining varnish. The anilox roller causes the varnish to be transferred to the plate cylinder, eventually causing the varnish to be transferred to the substrate. A designed photopolymer plate can be used to achieve a particular design. The plate cylinder may be made of a polymeric or elastomeric material. The polymer is used primarily as a photopolymer in the board and sometimes as a seamless coating on the sleeve. The photopolymer plate is made of a photopolymer which is hardened by ultraviolet light (UV). The photopolymer plate is cut to the desired dimensions and placed in a UV light exposure unit. One side of the plate is fully exposed to UV light to harden or cure the bottom of the plate. The plate was then turned over, a negative of a working plate (job) was mounted on the uncured side, and the plate was further exposed to UV light. This stiffens the plate in the image area. The plate is then processed to remove the uncured photopolymer from the non-image areas, which lowers the surface of the plate in these non-image areas. After treatment, the plate is dried and a post-exposure dose of UV light is given to cure the entire plate. The preparation of plate cylinders for flexographic Printing is described in Printing Technology, j.m. adams and p.a. dolin, delmr Thomson Learning, 5 th edition, p 359, 360.

For suitability for printing by flexography, a rotational viscometer DHR-2 from TA Instruments (cone geometry, diameter 40mm) is used, the curable varnish being at 25 ℃ and 1000s^-1The viscosity of (b) is necessarily in the range of about 0.01 to about 1 pas. Examples of curable varnishes by flexographic printing are described in international patent application No. WO2014067715a 1.

The manufacturing method claimed and described herein enables the selective application of different varnish deposits onto different surfaces of a security document, including the front and back of the security document, in a single printing process, thereby providing a security document with improved chemical and physical resistance. The methods of applying protective varnish on security documents according to the prior art are based on the exclusive use of flexographic printing or screen printing, and therefore the manufacture of security documents with variable coating thicknesses with said methods would require a large number of printing stations, resulting in complex, expensive and time-consuming manufacturing methods. Since steps b), c1) or c2) and d) are carried out in one printing process and at most two printing stations, the manufacturing method claimed herein overcomes the disadvantages. Further, the manufacturing method claimed herein remains cost-effective, since the inventive manufacturing method described herein enables selectively applying large deposits of varnish on the first substrate surface adjacent to the edge of the security feature and on the first area of the security feature surface facing away from the substrate.

In a preferred embodiment according to the invention, step c1) is carried out before step b), i.e. the curable varnish is printed by offset or flexography on a second substrate surface, which is different from the substrate surface covered by the security feature and the first substrate surface, and optionally on the security feature surface facing away from the substrate and the first substrate surface. Thus, a further embodiment according to the present invention relates to a manufacturing method comprising the steps of:

a) there is provided a security document comprising

A base material, a first metal layer and a second metal layer,

a security feature applied to or inserted into a portion of the substrate, wherein the security feature is selected from the group consisting of windowed security threads, security foils, security sheets, holograms and ink printed security features, having a security feature thickness t of at least 5 μm (microns)_fAnd a security feature surface facing away from the substrate, the security feature surface being comprised of a first region adjacent an edge of the security feature and a second region not adjacent the edge of the security feature;

c1) after step a), printing a curable varnish by offset or flexography on a second substrate surface, different from the substrate surface covered by the security feature and the first substrate surface, and optionally on the security feature surface facing away from the substrate and the first substrate surface;

b) after step c1), inkjet printing a radiation curable varnish onto the surface of the security feature facing away from the substrate and the first substrate surface adjacent the edge of the security feature, wherein the varnish deposit on the first substrate surface is equal to or higher than the varnish deposit on the first area adjacent the edge of the security feature and the varnish deposit on the first area is equal to or higher than, preferably higher than, the varnish deposit on the second area; and

d) after step b), curing the curable varnish to provide a protective coating covering the surface of the security feature facing away from the substrate, the surface of the first substrate and the surface of the second substrate;

wherein the varnish deposit on the second area is higher than the varnish deposit on the second substrate surface.

Another embodiment according to the present invention relates to a manufacturing process as described herein, wherein step b) of inkjet printing a radiation curable varnish onto the surface of the security feature facing away from the substrate and the surface of the first substrate adjacent to the edge of the security feature is performed before step c1), wherein the varnish deposit on the surface of the first substrate is equal to or higher than the varnish deposit on the first area adjacent to the edge of the security feature and the varnish deposit on the first area is equal to or higher than, preferably higher than the varnish deposit on the second area, and the manufacturing process further comprises a step e) performed between steps b) and c 1):

e) at least partially curing the radiation curable varnish printed in step b).

Thus, a further embodiment according to the present invention relates to a manufacturing method comprising the steps of:

a) providing a security document comprising:

a base material, a first metal layer and a second metal layer,

a security feature applied to or inserted into a portion of the substrate, wherein the security feature is selected from the group consisting of windowed security threads, security foils, security sheets, holograms and ink printed security features, having a security feature thickness t of at least 5 μm (microns)_fAnd a security feature surface facing away from the substrate, the security feature surface being comprised of a first region adjacent an edge of the security feature and a second region not adjacent the edge of the security feature;

b) after step a), inkjet printing a radiation curable varnish onto the surface of the security feature facing away from the substrate and the surface of the first substrate adjacent the edge of the security feature, wherein the varnish deposit on the surface of the first substrate is equal to or higher than the varnish deposit on the first area adjacent the edge of the security feature and the varnish deposit on the first area is equal to or higher than, preferably higher than, the varnish deposit on the second area;

e) after step b), at least partially curing the radiation-curable varnish printed in step b);

c1) after step e), printing the curable varnish by offset or flexography on a second substrate surface, different from the substrate surface covered by the security feature and the first substrate surface, and optionally on the security feature surface facing away from the substrate and the first substrate surface; and

d) after step c1), curing the curable varnish to provide a protective coating covering the surface of the security feature facing away from the substrate, the surface of the first substrate and the surface of the second substrate;

wherein the varnish deposit on the second area is higher than the varnish deposit on the second substrate surface.

In the manufacturing method claimed and described herein, it is preferred that in step c1) the curable varnish is printed only on the second substrate surface, i.e. step c1) comprises: the curable varnish is printed by offset or flexographic printing on a second substrate surface, different from the substrate surface covered by the security feature and the first substrate surface. These methods enable the use of two different varnishes in steps b) and c1), which is particularly useful for the manufacture of security documents, wherein the transparent protective coating covering the surface of the security feature facing away from the substrate and the surface of the first substrate is a flash paint and the protective coating covering the surface of the second substrate is a matte paint.

A further preferred embodiment according to the present invention relates to a manufacturing method as described herein and comprising steps a), b), c2) and d). Thus, a further preferred embodiment according to the present invention relates to a manufacturing method comprising the steps of:

a) providing a security document comprising:

a base material, a first metal layer and a second metal layer,

a security feature applied to or inserted into a portion of the substrate, wherein the security feature is selected from the group consisting of windowed security threads, security foils, security sheets, holograms and ink printed security features, having a security feature thickness t of at least 5 μm (microns)_fAnd a surface facing away from the substrate, the surface being comprised of a first region adjacent an edge of the security feature and a second region not adjacent the edge of the security feature;

b) inkjet printing a radiation curable varnish onto a surface of the security feature facing away from the substrate and a first substrate surface adjacent an edge of the security feature, wherein the varnish deposit on the first substrate surface is equal to or higher than the varnish deposit on a first region adjacent the edge of the security feature and the varnish deposit on the first region is equal to or higher than, preferably higher than, the varnish deposit on a second region;

c2) inkjet printing a radiation curable varnish on a second substrate surface, the second substrate surface being different from the substrate surface covered by the security feature and the first substrate surface; and

d) curing the curable varnish to provide a protective coating covering the security feature surface, the first substrate surface, and the second substrate surface, which are facing away from the substrate;

wherein the varnish deposit on the second area is higher than the varnish deposit on the second substrate surface.

Advantageously, the same radiation-curable varnish and the same inkjet printer are used in steps b) and c 2). Thus, a more preferred embodiment according to the present invention relates to a method of manufacturing a security document as described herein, the method of manufacturing comprising the steps of:

a) providing a security document comprising:

a base material, a first metal layer and a second metal layer,

a security feature applied to or inserted into a portion of the substrate, wherein the security feature is selected from the group consisting of windowed security threads, security foils, security sheets, holograms and ink printed security features, having a security feature thickness t of at least 5 μm (microns)_fAnd a security feature surface facing away from the substrate, the security feature surface being comprised of a first region adjacent an edge of the security feature and a second region not adjacent the edge of the security feature;

f) ink-jet printing a radiation curable varnish onto a surface of the security feature facing away from the substrate, a first substrate surface adjacent an edge of the security feature, and a second substrate surface, the second substrate surface being different from the substrate surface covered by the security feature and the first substrate surface; and

d) curing the curable varnish to provide a protective coating covering the security feature surface, the first substrate surface, and the second substrate surface, which are facing away from the substrate;

wherein

The varnish deposit on the first substrate surface is equal to or higher than the varnish deposit on the first region adjacent the edge of the security feature;

the varnish deposit on the first area is equal to or higher than, preferably higher than, the varnish deposit on the second area; and

the varnish deposit on the second area is higher than the varnish deposit on the second substrate surface.

Preferably, the curable varnish used in the manufacturing method claimed herein is a radiation curable varnish, and more preferably a UV-Vis curable varnish. When a UV-Vis curable varnish is used, step d) in the process described herein comprises:

d) UV-curing the radiation curable varnish to provide a protective coating, preferably a transparent protective coating, covering the surface of the security feature facing away from the substrate, the surface of the first substrate and the surface of the second substrate;

and step e) in the manufacturing method described herein comprises:

e) at least partially UV-curing the radiation-curable varnish printed in step b).

According to yet another aspect the present invention relates to a method of imparting chemical and mechanical resistance, in particular chemical resistance, to a security document comprising a substrate and a security feature applied to or inserted into a portion of the substrate, wherein the security feature is selected from the group consisting of windowed security threads, security foils, security sheets, holograms and ink-printed security features, having a security feature thickness t of at least 5 μm (micrometres)_fAnd a security feature surface facing away from the substrate, the security feature surface being comprised of a first region adjacent an edge of the security feature and a second region not adjacent the edge of the security feature, wherein the method comprises the steps of:

b) inkjet printing a radiation curable varnish onto a surface of the first substrate facing away from the substrate security feature and adjacent an edge of the security feature, wherein the varnish deposit on the first substrate surface is equal to or higher than the varnish deposit on a first region adjacent the edge of the security feature and the varnish deposit on the first region is equal to or higher than, preferably higher than, the varnish deposit on a second region;

and

c1) printing a curable varnish by offset or flexographic printing on a second substrate surface, the second substrate surface being different from the substrate surface covered by the security feature and the first substrate surface, and optionally on the security feature surface facing away from the substrate and the first substrate surface;

or

c2) Inkjet printing a radiation curable varnish on a second substrate surface, the second substrate surface being different from the substrate surface covered by the security feature and the first substrate surface;

and

d) curing the curable varnish to provide a protective coating covering the security feature surface, the first substrate surface, and the second substrate surface, which are facing away from the substrate;

wherein

The varnish deposit on the second area is higher than the varnish deposit on the second substrate surface; and is

The protective coating covering the surface of the security feature facing away from the substrate and the surface of the first substrate is transparent.

In the method of conferring chemical and mechanical resistance to a security document described herein, step c1) may be performed before step b). Optionally, step b) may be performed before step c1), in which case the method further comprises a step e) performed between steps b) and c 1):

e) at least partially curing the radiation curable varnish printed in step b).

In the method described herein, it is preferred that in step c1) the curable varnish is printed only on the second substrate surface.

A further preferred method of conferring chemical and mechanical resistance to a security document comprises the steps a), b), c2) and d).

The invention will now be described in more detail with reference to the non-limiting figures and non-limiting examples.

Some examples of security documents according to the invention will now be described in detail with reference to the accompanying drawings, which are not to scale for the sake of clarity:

fig. 1-3 schematically show a cross-section of a security document (100) according to the invention.

Fig. 4A and 4B schematically show a top view of a security document (100) according to the invention. Fig. 4C schematically shows a cross section of the security document (100) depicted by fig. 4A and 4B.

Fig. 1 schematically depicts a cross-section of a security document (100) according to the present invention, wherein the security document (100) comprises an opaque substrate (110), a security feature (120) applied to a portion of the substrate (110) and a protective coating (130A, 130B, 130C) covering a surface of the security feature (120) facing away from the substrate (110), a first substrate surface adjacent to an edge of the security feature (120) and a second substrate surface different from the substrate surface covered by the security feature (120) and the first substrate surface. The protective coating (130B, 130C) covering the surface of the security feature facing away from the substrate (110) and the surface of the first substrate is transparent. The security document (100) comprises an uncoated region on the same side of the security document as the security feature (120). A transparent protective coating (130C) covering the first substrate surface and having a thickness t_cEqual to the thickness t of the security feature (120)_fAnd a thickness t of a transparent protective coating (130B) covering the second region of the security feature (120)_b2The sum of (a) and (b). A thickness t of a transparent protective coating (130B) covering a first area of the security feature (120)_b1Equal to the thickness t of the transparent protective coating (130B) covering the second area_b2Thickness t_b2Is greater than the thickness t of the protective coating (130A) covering the surface of the second substrate_a. Further, the thickness t of the security feature_fIs greater than the thickness t of the protective coating (130A) covering the surface of the second substrate_a。

Fig. 2 schematically depicts a cross-section of a security document (100) according to the invention, wherein the security document (100) comprises a substrate (110), a security feature (120) applied to a portion of the substrate (110) and a protective coating (130A, 130B, 130C) covering a surface of the security feature (120) facing away from the substrate (110), a first substrate surface adjacent to an edge of the security feature (120) and a second substrate surface, the second substrate surface being different from the substrate surface covered by the security feature (120) and the first substrate surface. The protective coating (130B, 130C) covering the surface of the security feature facing away from the substrate (110) and the surface of the first substrate isIs transparent. A transparent protective coating (130C) covering the first substrate surface and having a thickness t_cIs greater than the thickness t of the security feature (120)_fAnd a thickness t of a transparent protective coating (130B) covering the second region of the security feature (120)_b2The sum of (a) and (b). A thickness t of a transparent protective coating (130B) covering a first area of the security feature (120)_b1Is greater than the thickness t of the transparent protective coating (130B) covering the second area_b2Thickness t_b2Is greater than the thickness t of the protective coating (130A) covering the surface of the second substrate_a. Further, the thickness t of the security feature_fIs greater than the thickness t of the protective coating (130A) covering the surface of the second substrate_a。

Fig. 3 depicts a screenshot of a security document (100) according to the present invention, wherein the security feature (120) is a windowed security thread inserted into a portion of a substrate (110). For reasons of simplicity, the portion of the windowed security feature that is embedded in the substrate (110) is not shown. With respect to FIG. 1, the thickness t of the transparent protective coating (130C) covering the first substrate surface_cEqual to the thickness t of the security feature (120)_fAnd a thickness t of a transparent protective coating (130B) covering the second region of the security feature (120)_b2The sum of (a) and (b). A thickness t of a transparent protective coating (130B) covering a first area of the security feature (120)_b1Equal to the thickness t of the transparent protective coating (130B) covering the second area_b2Thickness t_b2Greater than the second substrate surface (110)_a) Thickness t of the protective coating (130A)_a. Further, the thickness t of the security feature_fIs greater than the thickness t of the protective coating (130A) covering the surface of the second substrate_a。

Fig. 4A, 4B and 4C show a security document (100) according to the invention. In particular, fig. 4A schematically shows a top view of a security document (100) according to the invention from the side of the security document on which the security feature is applied, while fig. 4B schematically shows a top view of the same security document (100) from the opposite side of the security document. As shown in fig. 4A and 4B, the transparent protective coating (130A, 130B, 130C) covers the entire surface of the substrate (110). Fig. 4C schematically shows a cross-section of the security document (100) depicted by fig. 4a along the axis a-a'.

Examples

The invention will now be described in more detail with reference to non-limiting examples.

I. General procedure for the preparation of Security documents

A first metallized foil (F1) (H1010 spangle foil from PROFOIL, www.profoil.com, thickness of about 10 μm determined by cross-sectional observation on a microscope) was used as the security feature for examples E1-E3 and comparative examples C1-C6. After the adhesive layer (from BASF) was applied by hand (k coater bar 0)HSL 9032) was applied to the foil surface opposite the metal layer, a first metallized foil F1(120) (20mm x 20mm) was applied to a polymer substrate (45mm x 45mm) (Guardian from CCL Secure) by hot embossing at 150 ℃ with a laboratory equipment (HSG-CC-heat seal from Brugger Feinmechanik mulchen)^TM) To provide a first substrate on a portion of which is applied a metallized foil F1 as a security feature.

A second metallized foil (F2) (commercial hot stamped foil, thickness about 10 μm) was used as the security feature for examples E4-E5 and comparative examples C7-C13. A second metallized foil (F2) (120) (22 mm. times.12 mm) was applied to a polymer substrate (45 mm. times.30 mm) (Guardian from CCL Secure) by hot embossing at 150 ℃ with a laboratory equipment (HSG-CC-heat seal from Brugger Feinmechanik Munich)^TM) To provide a second substrate having a metallized foil F2 applied over a portion thereof as a security feature.

UV-curable varnishes were prepared by mixing the components listed in Table 1 using a Dispermat (LC220-12) at 1000rpm for 1 hour at room temperature. Use of UV-curable varnish Haake Roto-Visco RV1 with Cone (DHR-2 from TA Instruments, Cone planar geometry, diameter 40mm) determined at 45 ℃ and 1000s^-1The viscosity at that time was 12.5 mPas.

Table 1 UV-curable varnish compositions:

the UV-curable varnish was applied by Drop On Demand (DOD) inkjet printing using a KM1024i inkjet head (from Konica Minolta) onto the first and second polymeric substrates bearing the first (F1) and second (F2) metallized foil, respectively, covering the metallized foil (F1, F2) facing away from the surface of the substrate, the first polymeric substrate surface adjacent to the edge of the metallized foil and the second substrate surface, which is different from the substrate surface and the first substrate surface covered by the metallized foil (F1, F2). Varnish deposit (g/m)²) Summarized in table 2.

The applied inkjet varnish was cured by irradiation using a conveyor (Aktiprint mini 18-2; 12 m/min) and Hg-lamps (power of 80Watt/cm for 2 tubes), corresponding to 500mJ/cm²To provide a transparent protective coating covering the surface of the metallized foil (F1, F2) facing away from the substrate, the surface of the first substrate adjacent to the edge of the metallized foil (F1 or F2), and the surface of a second substrate different from the surface of the substrate covered by the metallized foil (F1 or F2) and the surface of the first substrate. Microscopic analysis of the obtained samples confirmed the ratio between the varnish deposit on the surface and the thickness of the resulting clear coating covering said surface. For example, 7g/m²The varnish deposit of (2) resulted in a coating thickness of about 6.5 μm and 30g/m²The varnish deposit of (2) resulted in a coating thickness of about 29.5 μm.

Evaluation of chemical resistance

II.a general procedure for the evaluation of chemical resistance to acetone

Samples E1-E5 and C1-C13 prepared as described in item I above were immersed in acetone for 5 minutes at room temperature. The sample was removed from the solvent and dried at room temperature for several seconds. The appearance of the foil was evaluated according to the scale described in table 2 below.

General procedure for evaluation of chemical resistance to sodium sulfide solution

Samples E1-E5 and C1-C13 were immersed in aqueous sodium sulfide (124g/l) for 30 minutes at room temperature. The sample was removed from the solution, rinsed with deionized water, and dried with a light wipe of cotton fabric. The appearance of the foil was evaluated according to the scale described in table 2 below.

TABLE 2 grades for chemical resistance test

Grade	Test results
		1	Complete destruction of security features (metallized foil)
2	Significant change in security feature (metallized foil), i.e. more than 50% of the security feature is destroyed
		3	Significant change in security feature (metallized foil), i.e. less than 50% of the security feature is destroyed
4	Macroscopic minor changes in security features (metallized foils)
		5	The security feature (metallised foil) is unchanged, i.e. completely retained

Table 3 summarizes the results obtained in the chemical resistance tests of samples E1-E5 according to the invention and comparative samples C1-C13, based on the grades described in table 2. The resistance test values of Table 3 are the average of 2 samples of C1-C6 and E1-E3 in the acetone resistance test, 3 samples of C1-C6 and E1-E3 in the sodium sulfide resistance test, 5 samples of C7, and 2 samples of E4-E5 and C8-C13.

TABLE 3 chemical resistance test results

a) The first region (F1, F2) of the metallized foil is the region of the surface of the metallized foil facing away from the substrate, which is bounded by the edge of the metallized foil (F1 or F2), and has a constant width w of about 2mm for the metallized foil F1_b1And a constant width w of about 2mm for the metallized foil F2_b1。

b) The second region of the metallized foil (F1, F2) is the region of the surface of the metallized foil (F1, F2) facing away from the substrate, which is complementary to the first region of the surface of the metallized foil facing away from the substrate, and which has an area of 16mm x 16mm for metallized foil F1 and an area of 18mm x 8mm for metallized foil F2.

c) The first substrate surface is the substrate surface adjacent to an edge of a metallized foil (F1 or F2), the metallized foil (F1) having a constant width w of about 3mm for the first substrate carrying the first metallized foil F1_cThe metallized foil (F2) has a constant width w of about 2mm for a second substrate carrying a second metallized foil F2_c。

d) The second substrate surface is the substrate surface surrounding or abutting the first substrate surface, i.e. bounded internally by an area of 26mm x 26mm of the first substrate carrying the first metallized foil F1 and an area of 26mm x 16mm of the second substrate carrying the second metallized foil F2, and bounded externally by an area of 32mm x 32mm of the first substrate carrying the first metallized foil F1 and an area of 40mm x 25mm of the second substrate carrying the second metallized foil F2.

As demonstrated in table 3, no improvement in chemical resistance, in particular to solvents such as acetone and sodium sulfide solutions, was observed for samples C2, C8 and C9 characterized by the thickness of the protective coating layer typically used on security documents (such as banknotes) when compared to uncoated reference samples C1 and C7.

The higher uniform varnish deposits (samples C3-C4, C10-C12) resulting in a larger uniform coating thickness provide resistance to solvents such as acetone, but do not effectively protect the security features from sodium sulfide solution.

Only very large varnish deposits resulting in very large uniform protective coating thicknesses (C5, C6, and C13) provide good protection against solvents and sodium sulfide solutions. However, such large varnish thicknesses over the entire surface of security documents, such as banknotes, do not constitute a viable solution for technical reasons, such as the stiffness of the coated security documents, and for cost reasons.

Samples E1-E5 according to the invention show the effect of a variable protective coating thickness on the surface of a security document having a greater coating thickness (t) over a first area of the first substrate surface adjacent to the edge of the metallized foil (F1, F2) and the surface of the metallized foil (F1, F2) facing away from the substrate than over the remaining surface of the security document_c，t_b1) Wherein the coating thickness t on the surface of the first substrate is compared to the unpainted reference samples (C1 and C7) and the uniformly painted samples (C2-C4 and C8-C12)_cGreater than the thickness t of the security feature_fAnd is greater than or equal to the coating thickness t on the first area of the metallized foil_b1。

It can be seen from samples E1-E5 that when a large varnish deposit (15-30 g/m) is applied on the first area of the metallized foil (F1, F2) and the first substrate surface²For the particular UV-curable varnish used herein and the particular metalized foil thickness used herein), the metalized foil (F1, F2) was well protected, resulting in a large transparent protective coating thickness, and an intermediate varnish deposit (7 g/m)²The particular UV-curable varnish used herein and the particular metalized foil thickness used herein) results in an intermediate coating thickness on the second region of the metalized foil (F1, F2) while maintaining a typical varnish deposit (2 g/m)²) Resulting in a typical coating thickness on the surface of the second substrate.

Samples E1-E5 exhibited excellent resistance in both the sodium sulfide test and the acetone test, which is reflected in no or little change in the appearance of the metallized foil.

Haze measurement

The haze of the UV curable inkjet varnish and standard UV curable flexographic varnish of table 1 (example C4 as described in international patent application publication No. WO2014067715a 1) was measured using a DC 650 spectrophotometer (from DATACOLOR) according to ASTM D1003 (standard test method for haze and light transmission of transparent plastics).

The UV curable inkjet printing varnish and standard UV curable flexographic printing varnish of table 1 (example C4 as described in international patent application publication No. WO2014067715a 1) were each applied to a BOPP polymeric banknote substrate. Each 5g/m was obtained by ink-jet printing at 720dpi using an ink-jet print head KM1024i²Varnish deposit and 30g/m²Varnish deposition the UV curable inkjet printing varnish of table 1 was applied.

The K-bar hand coater Nr 0 (from RK Printcoat Instruments) was used at 5g/m²Varnish deposition standard UV curable flexographic varnish (example C4 as described in international patent application publication No. WO2014067715a 1) was applied.

The uncoated polymeric banknote substrate had a haze of about 3%.

The haze of a polymeric banknote substrate coated with a standard UV curable flexographic varnish (example C4 as described in international patent application publication No. WO2014067715a 1) was about 10%. Such UV curable flexographic printing varnishes are not suitable at 5g/m²Printed on the surface of the security feature and on the first substrate surface. Can be less than about 5g/m²Preferably at about 1g/m²～3g/m²The varnish deposit of the UV curable flexographic varnish in between is applied on the second substrate surface. However, for the specific case of a security document in which a portion of the substrate to which the security feature is applied is a transparent polymer, such UV-curable flexographic printing varnish should be omitted on the surface of the transparent polymer portion opposite to the surface of the transparent polymer portion to which the security feature is applied, in order to ensure that the properties of the security feature applied to the transparent polymer are not compromised.

At 5g/m²Varnish depositAnd 30g/m²The haze of the polymeric banknote substrate coated with the UV curable inkjet printing varnish of table 1 was similar (± 1%) to the haze of the unpainted polymeric banknote substrate under the varnish deposit. Such UV curable inkjet varnish may be printed on any surface of a security document, including on the surface of a security feature and the surface of a first substrate.