LAYER STRUCTURE WITH MODIFIED STRUCTURE, AND PRODUCTION THEREOF

Abstract

The invention relates to a layer structure containing: (A) a first transparent radiation-engravable layer (A) with a first surface a1) and a second surface a2) which runs substantially parallel to the surface a1), said first layer (A) having a colorful or black part-engraving, said engraving being generated by means of nonionizing electromagnetic radiation (E), on the first surface a1) which forms a first outer surface of the layer structure; (B) optionally an additional transparent radiation-engravable layer (B) with a first surface b1) facing towards the first layer (A) and another surface b2) facing away from the first layer (A) and running substantially parallel to the surface b1); and (C) optionally at least one additional transparent plastic layer (C), wherein the additional layer (C) is selectively provided in one of a group of options consisting of: on the face of the first surface a1) of the layer (A), on the face of the additional surface b2) of the additional layer (B), between the two layers (A) and (B), or, in the event of additional layers (C), a combination of at least two of said options, and an image of the colorful or black part-engraving is located on the surface of the layer structure in the form of a nontransparent structural modification forming an additional outer surface of the layer structure and lying opposite the first surface a1). The invention likewise relates to the production of the layer structure as well as to a security document containing the layer structure according to the invention.

Claims

1. A layer construction comprising: (A) a first transparent radiation-engravable layer (A) having a first surface a1), and a second surface a2) that runs parallel to the first surface a1), wherein the first layer (A) on its first surface a1) which forms a first outer face of the layer construction has a colored or black engraving over a part of the area that has been produced by means of nonionizing electromagnetic radiation (E); (B) a further transparent radiation-engravable layer (B) having a first surface b1) facing in a direction of the first layer (A) and a further surface b2) facing in a direction away from the first layer (A) and parallel to the first surface b1); (C) at least one additional transparent polymer layer (C), wherein arrangement of an additional layer (C) is electively selected from the group consisting of: on the side of the first surface a1) of layer (A), on a side of a further surface b2) of the further layer (B), between the two layers (A) and (B), or a combination of at least two of these in the case of multiple further layers (C), wherein an image of the colored or black engraving over part of the area is present in the form of a nontransparent structural alteration at the surface of the layer construction forming a further outer face of the layer construction and is opposite the first surface a1).

2. The layer construction as claimed in claim 1, wherein the surface of the layer construction which is opposite the first surface a1) and forms a further outer face of the layer construction has an altered structure at least at sites that are at an angle in the range from 45° to 90° relative to an axis at right angles through the layer construction proceeding from the engraving.

3. The layer construction as claimed in claim 2, wherein the altered structure has a cloudy or milky appearance, with a turbidity within a range from 20 to 500 NTU.

4. The layer construction as claimed in claim 1, wherein layer (B) at sites with the altered structure has a layer thickness at least 0.001 mm thicker than at the sites without altered structure.

5. The layer construction as claimed in claim 1, wherein at least one of layers (A), (B) and (C) has one of the following properties: I. a layer thickness within a range from 10 μm to 10 000 μm; II. a radiation transmittance of ≥2% to ≤99.95%, for the chosen radiation, determined by the UV-VIS-NIR-MIR method to DIN EN ISO/IEC 17025.

6. The layer construction as claimed in claim 1, wherein at least layer (A), includes a thermoplastic selected from the group consisting of polymers of ethylenically unsaturated monomers, polycondensates of bifunctional reactive compounds, and polyaddition products of bifunctional reactive compounds, and combinations of at least two of these.

7. The layer construction as claimed in claim 1, wherein layer (A), comprises at least one additive having an absorption maximum in the wavelength range of focused nonionizing electromagnetic radiation, or wherein layer (A), is coated with at least one additive in a coating composition having an absorption maximum in the wavelength range of the focused nonionizing electromagnetic radiation.

8. A process for producing a colored layer construction, comprising the steps of: i) proceeding from an uncolored layer construction at least having i)1. a first transparent radiation-engravable layer (A) having a first surface a1), and a second surface a2), wherein the surfaces are parallel to one another, i)2. optionally, a further transparent radiation-engravable layer (B) having a first surface b1) facing in a direction of the first layer (A) and a further surface b2) facing in an opposite direction away from the first layer (A); ii) contacting at least part of the first surface a1) of the first transparent radiation-engravable layer (A) with a coloring bath (F) containing the colorant; iii) irradiating the layer construction from step ii) with focused nonionizing electromagnetic radiation from a side remote from the coloring bath (F) through the surface a2) or optionally, also b2).

9. The process as claimed in claim 8, wherein the layer construction in step iii) is irradiated through the further layer (B) onto the first layer (A).

10. The process as claimed in claim 8, wherein at least layer (A), includes a thermoplastic selected from the group consisting of polymers of ethylenically unsaturated monomers, polycondensates of bifunctional reactive compounds and polyaddition products of bifunctional reactive compounds, and combinations of at least two of these.

11. The process as claimed in any of claim 8, wherein layer (A), and optionally layer (B), comprise at least one additive having an absorption maximum in the wavelength range of the focused nonionizing electromagnetic radiation, or wherein layer (A), and optionally layer (B) are coated with at least one additive in a coating composition having an absorption maximum in the wavelength range of the focused nonionizing electromagnetic radiation.

12. The process as claimed in claim 11, wherein the additive comprises at least one or more of organic IR absorbers and/or inorganic IR absorbers.

13. The process as claimed in claim 8, wherein the coloring bath (F) comprises at least one dye selected from the group consisting of solvent dyes, disperse dyes according to the Colour Index classification, and mixtures of these dyes.

14. The process as claimed in claim 8, wherein the coloring bath (F) comprises: a) one of a solvent and a dispersant, b) at least one colorant comprising at least one dye from the group consisting of solvent dyes, disperse dyes according to the Colour Index classification, and a mixture of these.

15. A security document comprising a layer construction as claimed in claim 1.

16. A security document comprising a layer construction produced in the process as claimed in claim 8.

Description

FIGURES

[0206] The figures that follow show by way of example how structural alteration and the colored or black engraving over part of the area are introduced simultaneously into the layer construction by laser, without restriction to these embodiments. The figures show:

[0207] FIG. 1a: a schematic diagram of a layer construction of the invention as a side view in which both the colored or black engraving over part of the area and the nontransparent structural alteration are introduced by laser as a perpendicular image relative to one another;

[0208] FIG. 1b: a schematic diagram of a layer construction of the invention as in FIG. 1, but with layer construction rotated by about 45° relative to the laser;

[0209] FIG. 1c: a schematic diagram of a layer construction of the invention as in FIG. 1, but with laser rotated by about 45° relative to the layer construction;

[0210] FIG. 2: a schematic diagram of the production process.

[0211] FIG. 1a shows how a color 120 was introduced on the first surface a1) 10 and a nontransparent structural alteration 110 on the further surface a2) 20 under the conditions described above for the examples onto a layer construction 1 produced as described in example 1 or 2. For laser irradiation of the layer construction 1 in the form of laminate A, the laser light 100 was first directed vertically onto the further surface a2) 20 of layer construction 1. When the laser beam 100 hit the further surface a2) 20 of layer construction 1, the nontransparent structural alteration 110 was created. The laser beam 100 then ran vertically to the further surface a2) 20 through the thickness D of the layer construction 1. When it hit the first surface a1) 10, the laser light 100 that had been passed through the layer construction 1, once it had made the structural alteration 110, created the colored or black engraving 120. This coloring was possible since the first surface 10 was in direct contact with a coloring bath 200.

[0212] FIG. 1b shows the same process as shown in FIG. 1a, with the layer construction 1, but especially the further surface 20 of the layer construction 1, rotated by a few degrees relative to the angle of incidence of the laser, such that the laser beam 100 hit the further surface 20 of the layer construction 1 at an angle of about 45°. The beam path of the laser light 100 is likewise through the thickness D of the layer construction, with the laser beam covering a somewhat greater distance than in the arrangement in FIG. 1. As a result, the non-transparent structural alteration 110 that constitutes the image of the colored or black engraving 120 over part of the area is in a slightly shifted arrangement relative to the normal through the layer construction 1.

[0213] FIG. 1c shows the same process as shown in FIG. 1a, with the laser and hence the laser light 100 rotated by a few degrees relative to the further surface 20 of the layer construction 1, such that the laser beam 100 hit the further surface a2) 20 of the layer construction 1 at an angle of about 45°. The beam path of the laser light 100 is likewise through the thickness D of the layer construction, with the laser beam covering a somewhat greater distance than in the arrangement in FIG. 1. As a result, the non-transparent structural alteration 110 that constitutes the image of the engraving 120 is in a slightly shifted arrangement relative to the normal through the layer construction 1.

[0214] FIG. 2 shows the steps of the process of the invention. In step i) 300, the uncolored layer construction 1 was provided in the form of laminate A. As described above for FIG. 1a, this takes place on the workpiece carrier of a Foba D84S laser apparatus. For step ii) 400, a coloring bath (F) 200 was placed beneath the layer construction 1 such that only the first surface a1) 10 was in contact with the coloring bath (F) 200. In the third step iii) 500, the layer construction 1 was first irradiated by means of laser beam 100 onto the further surface a2) 20 of the layer construction 1, with creation of a non-transparent structural alteration 110 on the further surface a2) when hit by the laser light 100. Thereafter, the laser light hit the first surface a1) 10 in order to create the colored or black engraving 120 over part of the area there.