DE102019107177A1 - Process for the production of visual effects on a printing material - Google Patents

Abstract

A method for producing visual effects on a printing material with a surface made of plastic, the method including an embossing process in an embossing device with an embossing element, the embossing element having an embossing area, wherein the printing material surface in the embossing device is brought into embossing contact with the embossing area for an embossing time , wherein during the embossing process between the embossing element and the printing substrate surface a plastic film element is provided at least in the embossing area, the printing substrate surface having a first melting temperature, the plastic film element having a second melting temperature, the embossing element having an embossing temperature, the second melting temperature greater than the first melting temperature and wherein the embossing temperature is between the first melting temperature and the second melting temperature and wherein the printing substrate surface has a first surface roughness wherein the plastic film element has a second surface roughness, wherein the first surface roughness is in the inverse size ratio to the second surface roughness and wherein the embossing element has an embossing element roughness which is smaller (or equal to) the smaller roughness of the two surface roughnesses.

Description

The present description relates to and claims a method for producing visual effects on a printing material with a surface made of plastic, in which embossing techniques are used.

Embossing techniques are known in many ways. They are characterized by the fact that they can be used to apply reliefs or the like to surfaces by means of an embossing stamp (die). The embossing motif can also be pressed deeper into the material to be embossed.

A so-called stamping foil is often used in the stamping process. The embossing foil serves as a carrier and transfer medium for the printing ink onto the printing material. In this case, one speaks of foil stamping. With foil stamping, the printing form / stamp is brought to a certain temperature / printing temperature and maintained.

The stamping foil has several layers. The layers are in particular a carrier layer, a separating layer and, if appropriate, various transfer layers. During the embossing process, the separating layer melts in the contact area of the embossing stamp and the transfer layers are transferred to the surface of the printing material and anchored there.

The strength and duration of the contact pressure as well as the temperature depend on the type of embossing foil or its transfer layers, the fineness of the print image or the embossing tool and the type of printing material (source: training guide for print processing of the Federal Association of Printing and Media (bvdm), Wiesbaden ). The success of the embossing, especially in the case of plastic surfaces, essentially depends on the quality of the transfer layers, i.e. their structure and composition, but also on the deposition process and the process parameters selected, which further increases the complexity in the embossing process.

To this extent, there is a need for a simplification of the embossing techniques when embossing motifs, in particular on plastic surfaces.

An object of an embodiment of the present invention can therefore be seen in providing a method which enables the production of motifs or visual effects in a simple manner on and on plastic surfaces, both from a procedural point of view and with a view to the composition or the Structure of the stamping foil itself allows.

According to one aspect of the invention, such an embodiment relates in its core concept to a method for producing visual effects on a printing material with a surface made of plastic, the method including an embossing process in an embossing device with an embossing element, the embossing element having an embossing area, the printing material surface in the embossing device is brought into embossing contact with the embossing area for an embossing time, wherein during the embossing process between the embossing element and the printing substrate surface a plastic film element is provided at least in the embossing area, the printing substrate surface having a first melting temperature, the plastic film element having a second melting temperature, the embossing element a Having embossing temperature, wherein the second melting temperature is greater than the first melting temperature and wherein the embossing temperature between the first melting temperature and the second Sc melting temperature and wherein the substrate surface has a first surface roughness, wherein the plastic film element has a second surface roughness, wherein the first surface roughness is in the inverse size ratio to the second surface roughness and wherein the embossing element has an embossing element roughness which is less than (or equal to) the smaller of the two Surface roughness is.

According to the invention, it has been shown that a targeted and suitable choice of a plastic film element that is free of separating layer and transfer layer can produce a targeted visual effect or motif on the surface of a printing material. The latter is the case when defined process parameters with regard to the melting temperatures of the substrate surface and the plastic film element as well as the embossing temperature are observed and care is taken to ensure that the surface roughness of the substrate surface, the plastic film element and the embossing element are in a defined relationship to one another. In the context of the development preceding the invention, it was possible to work out that a visual effect or motif can be achieved on the printing substrate surface when the surface roughness of the plastic film element is inversely related to the surface roughness of the printing substrate surface.

The reversal of the proportions can in this respect mean a reversal in the proportions of the roughness. The order of magnitude can include, for example, a power of ten.

This means that if, for example, the first surface roughness or the roughness of the printing substrate surface is in the range from approximately 0.3 μm to approximately 1.2 μm, the second surface roughness or the roughness of the plastic film element is in the range of can be equal to approx. 3.0 µm to approx. 6.0 µm.

The reversal of the size ratios would then mean that the first surface roughness is in the range from approx. 3.0 µm to approx. 6.0 µm, whereas the second surface roughness or the roughness of the plastic element has a value in the range of approx. 0.3 µm to approximately 1.2 µm.

The ranges mentioned and each of the values contained therein have been found to be particularly preferred and advantageous according to the invention.

In a particularly preferred embodiment, for example, the first surface roughness can be approximately 0.5 μm and the second surface roughness approximately 4 μm or any other value in the range from approximately 3.0 μm to approximately 6.0 μm accepts. In contrast, according to the invention, the inversion can mean that the first surface roughness or the surface roughness of the printing substrate surface is, for example, approximately 4.0 μm and the second surface roughness is approximately 0.5 μm or any other value in the range between approximately 0 .3 µm to approximately 1.2 µm.

In this case, an expanded finding also consists in the fact that it is advantageous if the surface roughness of the embossed area is essentially aligned with the respective smaller surface roughness of the two surface roughnesses.

Furthermore, the roughness in the embossed area is preferably smaller than the smaller of the surface roughness of the first or the second surface roughness. The latter in particular because a potential influence of the embossing element on the motif to be embossed or the visual effect to be embossed can thereby be considerably reduced or even minimized or even eliminated.

Furthermore, it is provided according to the invention that the plastic film element has a melting temperature (second melting temperature) which is deliberately above the melting temperature of the printing material surface (first melting temperature) and also above the embossing temperature of the embossing element or its embossing area. This is not only in contrast to the prior art, but also aims to ensure that, on the one hand, a sufficient temperature effect can be achieved on the plastic film element and, by means of it, on the printing substrate surface and, on the other hand, it is ensured that there is no melting sticking during the embossing process the embossing element and the foil element comes.

The process safety is also served by the fact that in the melting temperature distance between the second melting temperature and the first melting temperature, the embossing temperature is preferably set in the half of the melting temperature distance facing the second melting temperature.

According to a preferred embodiment, the melting temperature distance assumes a range from 80 ° C. to 120 ° C. or 90 ° C. to 110 ° C. or is particularly preferably 100 ° C. or any other value or value range within the specified range .

The absolute value for the first melting temperature is in a range of approx. 140 ° C. and approx. 180 ° C. or particularly preferably approx. 150 ° C. or any other value within the specified range.

The printing material surface can for example be made of a PVC plastic, as is the case with plastic cards or chip cards or the like, for example.

The absolute value for the second melting temperature is in a range from approx. 230 ° C. to approx. 260 ° C. or particularly preferably approx. 250 ° C. or any other value within the specified range.

The plastic film element can in this respect be made from a PET plastic, for example.

The embossing temperature is preferably in a range from approx. 200 ° C. to approx. 220 ° C. or particularly preferably approx. 210 ° C. or any other value within the specified range.

In the context of the method according to the invention, it has also proven to be advantageous if the printing material surface in the embossing device is brought into embossing contact with the embossing area for an embossing time in the range from 0.2 seconds to 0.5 seconds.

Furthermore, it could be shown in the context of the development led to the invention that it has an advantageous effect on the embossing result if at least in the embossing area the plastic film element has a thickness of approx. 10 µm to approx. 30 µm.

In addition to the method described above, another advantageous aspect according to the invention also consists in providing a printing material with a plastic surface which has a printing material surface with a visual effect, which printing material surface was produced with a visual effect by the method described above.

Further features, advantages, effects and details emerge from the following description, in which at least one exemplary embodiment is described in detail, possibly with reference to one or more drawings. Described and / or graphically represented features form the subject matter individually or in any meaningful combination, possibly also independently of the claims, and in particular can also be the subject matter of one or more separate applications. Identical, similar and / or functionally identical parts are provided with the same reference symbols.

• 1 eine vereinfachte seitliche Darstellung einer Prägevorrichtung;
• 2 eine Darstellung für einen Prägestempel mit einem Prägemotiv;
• 3 eine Kunststoffkarte mit einem ausgeprägten Motiv.

They show schematically:

• 1 a simplified side view of an embossing device;
• 2 a representation of an embossing stamp with an embossing motif;
• 3 a plastic card with a distinctive motif.

1 shows schematically in a simplified representation an embossing device 3 within the meaning of the present invention.

To the embossing device 3 in 1 can be seen: a counter pressure form 11 , a substrate 2 with a substrate surface 6th with a surface roughness 8th (first surface roughness 8th ), a plastic film element / stamping film 7th with a surface roughness 9 (second surface roughness 9 ), a stamping element or stamp 4th with an embossed area 5 with a surface roughness 10 , a hot plate 12th for heating the die 4th on the embossing temperature or process temperature.

1 shows the embossing device 3 in the status before the actual embossing process, during which the embossing stamp 4th with its embossed area 5 against the stamping foil 7th and against the substrate 2 , for example a chip card or other plastic card made of PVC, for example, or its surface 6th to create a motif 1 ( 3 ) is directed. With the stamping foil 7th it is, for example, a PET film. The foils and process parameters can be defined as follows:

example 1

Roughness card / smooth Roughness foil / matt Roughness stamp Temperature stamp Minting time Thick stamping foil Melting temperature stamping foil approx. Melting temperature card material approx. 0.5 µm 4 µm 0.2 µm 210 ° C ± 10 ° C 0.2 s to 0.5 s 10 to 30 µm PET 250 ° C PVC 150 ° C 0.2 µm to 2 µm 2 µm to 10 µm 0.2 µm 210 ° C ± 10 ° C 0.2 s to 0.5 s 11 to 30 µm PET 250 ° C PVC 150 ° C 0.3 µm to 1.2 µm 3 µm to 6 µm 0.2 µm 210 ° C ± 10 ° C 0.2 s to 0.5 s 12 to 30 µm PET 250 ° C PVC 150 ° C

In the case of Example 1, embossing foils are used 7th used relative to the card material / printing material 2 are matt and vice versa, of course, the surface 8th of the map material 2 is smooth compared to the surface 9 the stamping foil 7th . This corresponds to the schematic in 1 presented situation. It should also be mentioned that the stamp pressure applied in the embossing process depends on the desired quality of the motif to be embossed 1 ( 3 ) can be selected. It should also be mentioned that the roughness 10 of the die 4th according to example 1 below or at the level of the smallest roughness value relative to the embossing foil 7th smoother map material surface 8th lies.

Example 2 below shows the roughness conditions in the embossing process with an embossing device 3 according to 1 is the inverse, for example 1.

Example 2

Roughness card / matt Roughness foil / smooth Roughness stamp Temperature stamp Minting time Thick stamping foil Melting temperature stamping foil approx. Melting temperature card material approx. 4 µm 0.5 µm 0.2 µm 210 ° C ± 10 ° C 0.2s to 0.5s 10 to 30 µm PET 250 ° C PVC 150 ° C 2 µm to 10 µm 0.2 µm to 2 µm 0.2 µm 210 ° C ± 10 ° C 0.2s to 0.5s 11 to 30 µm PET 250 ° C PVC 150 ° C 3 µm to 6 µm 0.3 µm to 1.2 µm 0.2 µm 210 ° C ± 10 ° C 0.2s to 0.5s 12 to 30 µm PET 250 ° C PVC 150 ° C

Therefore, the relatively smoother surface in this example 2 lies in the surface roughness 8th the stamping foil 7th . On the surface roughness of the die 4th in the area 5 (Embossing area) there were no changes compared to example 1.

In relation to 1 shows 2 an example of a schematic representation for an embossing element / embossing die 4th with a motive 1 , an embossing surface 10 in an embossed area 5 . The embossing area 5 has embossed recesses 14th on.

3 shows schematically the result of embossing a chip card made of PVC with the card chip 13 . The embossing according to the invention took place in the middle of the chip card surface 2 . There it becomes clear that the embossing is only in the contact area 15th , ie outside the embossing recesses 14th of the die 4th on the map surface 6th affects and thereby the motive 1 on the substrate / chip card 2 is transmitted.

It should be understood that while the foregoing detailed description and drawings depict certain exemplary embodiments of the invention, they are intended for purposes of illustration only and are not to be construed as limiting the scope of the invention. Various modifications of the embodiments described are possible without departing from the scope of the following claims and their range of equivalency. In particular, features of the exemplary embodiments which are not mentioned in the claims also emerge from this description and the figures. Such features can also occur in combinations other than those specifically disclosed here. The fact that several such features are mentioned in the same sentence or in a different type of textual context does not therefore justify the conclusion that they can only occur in the specifically disclosed combination; Instead, it is to be assumed in principle that some of these features can also be omitted or modified, provided that this does not jeopardize the functionality of the invention.

Throughout the description and claims as a whole, the term “a” is used as an indefinite article and the number of parts is not limited to a single one. Should “a” have the meaning of “only one”, this should be understood from the context for the person skilled in the art or is uniquely revealed through the use of suitable expressions such as, for example, “a single”.

List of reference symbols

1

Visual effect, motif

2

Printing material / chip card

3

Embossing device

4th

Embossing element / stamp

5

Embossing area

6th

Substrate surface

7th

Plastic film element, stamping film

8th

Surface roughness of the substrate surface, first surface roughness

9

Surface roughness of the plastic film element, second surface roughness

10

Surface roughness in the embossing area 5

11

Counter pressure form

12

Heating plate

13

Card chip

14th

Embossing recesses

15th

Contact area of the die

Claims (15)

Method for producing visual effects (1) on a printing material (2) with a surface (6) made of plastic, wherein the method includes an embossing process in an embossing device (3) with an embossing element (4), wherein the embossing element (4) has an embossing area (5), wherein the printing material surface (6) in the embossing device (3) is brought into embossing contact with the embossing area (5) for an embossing time, wherein a plastic film element (7) is provided at least in the embossing area (5) between the embossing element (4) and the printing substrate surface (6) during the embossing process, wherein the printing material surface (6) has a first melting temperature, wherein the plastic film element (7) has a second melting temperature, wherein the embossing element (4) has an embossing temperature, wherein the second melting temperature is greater than the first melting temperature and the embossing temperature being between the first melting temperature and the second melting temperature, wherein the substrate surface (6) has a first surface roughness (8), wherein the plastic film element (7) has a second surface roughness (9), wherein the first surface roughness (8) is in inverse size ratio to the second surface roughness (9) and wherein the embossing element (4) has an embossing element roughness (10) which is smaller (or equal to) the smaller roughness from the two surface roughnesses (8; 9) . Procedure according to Claim 1 wherein the inversion of the size ratios comprises an inversion in the order ratio of the roughness of the first and the second surface roughness (8; 9). Procedure according to Claim 2 , where the order of magnitude includes a power of ten. Method according to one or more of the preceding claims, wherein the first surface roughness (8) is in the range from 0.2 µm to 2 µm or in the range from 0.3 µm to 1.2 µm or at 0.5 µm. Method according to one or more of the preceding claims, wherein the second surface roughness (9) is in the range from 2 µm to 10 µm or in the range from 3 µm to 6 µm or 4 µm. The method according to one or more of the preceding claims, wherein the first melting temperature and the second melting temperature form a melting temperature gap and wherein the Embossing temperature, in which half of the melting temperature distance facing the second melting temperature is established. Method according to one or more of the preceding claims, wherein the melting temperature distance assumes a range from equal to 80 ° C to equal to 120 ° C or equal to 90 ° C to equal to 110 ° C or is 100 ° C. Method according to one or more of the preceding claims, wherein the first melting temperature is in a range from 140 ° C and 180 ° C or at 150 ° C. Method according to one or more of the preceding claims, wherein the printing material surface (6) contains a PVC plastic. Method according to one or more of the preceding claims, wherein the second melting temperature is in a range from 230 ° C to 260 ° C or at 250 ° C. Method according to one or more of the preceding claims, wherein the plastic film element (7) contains a PET plastic Method according to one or more of the preceding claims, wherein the embossing temperature is in a range from 200 ° C to 220 ° C or at 210 ° C. Method according to one or more of the preceding claims, wherein the printing material surface (6) in the embossing device (3) is brought into embossing contact with the embossing area (5) for an embossing time in the range from 0.2 seconds to 0.5 seconds. Method according to one or more of the preceding claims, wherein the plastic film element (7) has a thickness in the range from 10 µm to 30 µm, at least in the embossed area (5). Printing substrate having a printing substrate surface (6) with a visual effect (1), produced by a method according to one or more of the preceding claims.

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