EP3915802A1 - Method for thermal embossing of substrates using sleeve technology - Google Patents

Abstract

The invention relates to a method for the thermal structure embossing of substrates with an embossing cylinder, the substrate (16) being guided along a heated embossing surface (3) of the embossing cylinder during embossing in order to transfer the structure of an embossing structure (4) formed in the embossing surface into the substrate ( 16) to shape. The embossing cylinder is an embossing sleeve (1) in the form of a sleeve designed as an interchangeable unit and is designed to be exchangeable for at least one other embossing sleeve, the embossing sleeve being able to be clamped onto a mandrel (13) inserted into the sleeve for assembly in an embossing system, and the embossing surface ( 3) of the embossing sleeve (3) is heated via the mandrel (13).

Description

The invention relates to a method for thermal structure embossing of particularly flexible substrates, such as transfer film or the like, the substrate being guided in particular in a web-like manner along a heated embossing surface of the embossing cylinder in order to form the structure of an embossed structure formed in the embossing surface in the substrate. The invention also relates to an embossing cylinder in the form of an embossing sleeve and a system for thermal structure embossing of substrates.

TECHNICAL BACKGROUND

The economical, but also flexible production of structured surfaces is moving more and more into the focus of modern product developments. The flexible design of surfaces is required by many industrial sectors, for example by the furniture industry for the finishing of kitchen fronts or furniture panels or by the construction industry for the finishing of building materials. The coating and finishing of, in particular, flat workpiece surfaces, such as chipboard, MDF panels for furniture, floors, interior and exterior cladding or the like, play a central role here. By replicating structures in the workpiece surface, effective and haptically appealing surfaces can be generated.

Various processes are available for the production of various surface structures, which are tailored to the coating process of the surface. Different manufactured embossing matrices are used, for example in the Ways of pressing melamine into the surface or a structure that is painted onto the surface.

Much finer structures can be achieved through the use of, in particular, flexible embossing substrates, such as, for example, transfer foil. Such transfer substrates have a surface with a three-dimensional structure that serves as an embossing stamp for the surface of a target substrate. For this purpose, the surface of the target substrate is first coated with a hardenable coating (e.g. resin or lacquer). Then, before the coating hardens, the structured substrate, e.g. the transfer film, is applied so that the embossed structure of the substrate is in contact with the coated surface of the target substrate. After the coated surface has cured, the structure of the substrate is embossed into the surface. This leaves a negative image of the surface structure of the substrate on the target surface.

In particular, the use of transfer film as a possible substrate, mentioned only as an example, offers the possibility of realizing very fine structures in the micro or nano range on workpiece surfaces. Diverse functional surfaces such as lotus blossom effects, moth eye effects or shark skin effects, light control effects, retroreflection, backlight effects, e.g. with a profile depth of 100 nm to 50 µm, can be created in this way.

The embossing structure is introduced into the substrate by hot embossing ("thermal structure embossing"). It is known for this purpose to bring a heated embossing roller into contact with the substrate and to let it run along the embossing roller, the embossing roller rotating in the process. This process usually takes place in the R2R process (roll-to-roll process). Acquaintance Systems such as those in the EP 2 258 564 B1 are shown, use solid embossing rollers for this purpose, in the outside of which the embossing structure is molded. Such systems are primarily characterized by the fact that changing the printed or embossed image is very complex, because the entire embossing roller has to be removed in order to change the embossed image. In addition, these solid embossing rollers can weigh up to several tons and a changeover, ie an exchange of the embossing pattern by exchanging the roller, is almost impossible in one-man operation. Another approach is to weld plate-shaped shims to form a cylindrical embossing shape. As a result, it is not necessary to remove the entire solid roller in order to change the embossed image, but this technology has the disadvantage that shim seams visible in the embossed image, ie weld seams across and, depending on the working width, also along the running direction. In addition, changing the shim elements is time-consuming and complicated.

Characteristic for thermal structure embossing processes are the high technical and financial effort required to change the embossing image. It is therefore the object of the present invention to propose a solution with which structured substrates can be produced in a cost-efficient and flexible manner by thermal structure embossing.

SUMMARY OF THE INVENTION

The object on which the invention is based is achieved by a method with the features of claim 1, by an embossing sleeve with the features of claim 14 and by a system for thermal structural embossing of substrates with the features of claim 15. Preferred embodiments of the invention are the subject of the subclaims.

The method according to the invention provides that the embossing cylinder is designed as an exchangeable embossing sleeve, i.e. the embossing cylinder is provided in the form of a sleeve designed as an exchangeable unit, which can be exchanged for at least one other embossing form in the form of a sleeve. Such sleeve-shaped embossing cylinders are known under the name "Sleeves" and are already used in flexographic printing. Sleeve systems include an expanding mandrel arranged in the embossing system, onto which the sleeve, that is the sleeve, is pushed and clamped by expanding the mandrel. Such a mandrel forms a base core or carrier core. In contrast to regular roller systems, the basic cores are permanently installed in the embossing system. The embossed image is formed on the outside of the sleeve so that the sleeve installed on the base core runs around like a solid roller. To change the embossed image, only the sleeve needs to be exchanged. According to the invention, the embossing surface of the embossing sleeve is heated via the mandrel. For this purpose, a temperature control device, for example in the form of a heating spiral or the like, can be provided in the mandrel or a basic cylinder core. The heat is emitted from the heating coil via the mandrel or the basic cylinder core into the sleeve and there it is conducted into the embossing surface, i.e. the heat is transferred from the mandrel via the inside of the embossing sleeve into the embossing sleeve. The mandrel heats the embossing sleeve from the inside.

It has been found that sleeve technology can be used successfully in thermal structure embossing and has a number of technical advantages. The use of sleeve technology in thermal structure embossing goes hand in hand with a significant reduction in process costs and increased flexibility. With sleeve technology, micro and nanostructures can be built into substrates, such as transfer foils, with high accuracy thermal imprint. In this sense, a further embodiment of the invention provides that the embossed structure comprises micro- and / or nanostructures.

Another embodiment of the invention provides that the embossing sleeve is seamless. A seamless or weldless sleeve is shaped like a sleeve and has a seamless, in particular continuously smooth surface structure into which the embossed structure is molded. The particular advantage is that, unlike in shim systems, no images of weld seams are formed in the substrate running on the sleeve. In particular, the embossed structure can also be seamless, i.e. the embossed structure does not have any seams or the like, but is molded directly into the embossed sleeve.

A further embodiment of the invention provides that the structure embossing of the substrate takes place in the roll-to-roll process (“thermal R2R embossing”) or by static embossing.

Another embodiment of the invention provides that the embossing sleeve comprises a hollow cylindrical body which is provided on its outer surface with a coating in which an embossing structure is formed, the coating being a first coating layer of nickel with a thickness of 120-180 μm , a second cladding layer made of copper with a thickness of 250-310 µm; and a third coating layer of chromium with a thickness of 15-25 µm. It has been found that a sleeve with such a layer structure optimally transfers the heat that is introduced into the sleeve via the heating device in the mandrel carrying the sleeve or the base cylinder core into the substrate.

A method for producing the embossing sleeve described herein provides that a hollow cylindrical blank is provided, on the outer jacket surface of which a coating is electroplated in several steps. This includes the galvanic build-up of a first coat of nickel with a layer thickness of 120-180 µm, the galvanic build-up of a second coat of copper with a layer thickness of 250-310 µm and the galvanic build-up of a third coat in the form of a chrome layer with a layer thickness from 15-25 µm. In addition, an embossed structure is introduced into the coating.

The three coat layers are applied one after the other, whereby advantageous intermediate layers are not excluded. The introduction of an embossed structure into the coating can take place after the application of the three cladding layers or in an intermediate step. For example, the embossed structure can be molded into the second jacket layer before the embossed sleeve is chrome-plated. The embossing sleeve blank is shaped like a sleeve and can be shaped like a straight circular cylinder with a through opening along its axis.

It has been found that, due to the layer structure of the embossing sleeve outlined above, flexible substrate webs can be efficiently modified and a highly precise embossed image that is particularly stable under thermal loads is generated in the substrate. Especially in the context of thermal R2R embossing using sleeve technology, consistently high-precision nano and microstructures, e.g. haptic surfaces, optical effect surfaces, security features such as embossed holograms, or functional surfaces from the field of bionics without visible defects, even in larger working widths, e.g. larger than 1.50 m, produce. The term structure is to be understood in connection with the present invention as a three-dimensional structure. The three-dimensional structure can be present, for example, in the form of motifs, holograms, numbers, letters or as a functional surface (for example as a lotus effect surface).

The embossed structure can be introduced into the coating using various methods, for example by means of etching (e.g. chemical or plasma etching), laser ablation (e.g. using pico or nano lasers), lithographic methods (e.g. electron beam lithography), engraving, galvanic methods, and / or erosion .

As indicated above, the thickness of the nickel layer is in the range of 120-180 µm, the thickness of the copper layer in the range of 250-310 µm and the thickness of the chromium layer in the range of 15-25 µm. Even better results can be achieved if the thickness of the nickel layer is in the range of 140-160 µm, the thickness of the copper layer is in the range of 270-290 µm and the thickness of the chromium layer is in the range of 18-22 µm. In a particularly preferred embodiment of the invention, a nickel layer is 150 μm thick, the copper layer is 280 μm thick and the chromium layer is 20 μm thick.

Basically, it is provided that the jacket layers are applied to the sleeve blank in the order in which they are numbered, i.e. the nickel layer is first applied to the blank cylinder. In a further step, the copper layer is applied. The chrome layer then encloses the first and second coating layers and serves as a protective chrome plating.

The embossed structure can be molded into the chrome layer. That means that the embossing structure is only in the embossing sleeve molded in when all jacket layers have been applied to the blank. For example, the embossed structure can be a nanostructure in the chromium layer with a structure depth of, for example, 100 nm to 500 nm, preferably 100 nm to 200 nm, more preferably 120 nm to 150 nm. In this regard, the structure depth is to be understood as the depth of the embossed structure introduced into the respective layer relative to the surface of the respective layer. Alternatively or additionally, an embossed structure, preferably in the form of a microstructure, can be introduced into the copper layer before the chrome layer is applied. The chrome layer, which is applied in a further process step, also serves as a protective chrome plating for the embossed structure in the copper layer. In this embodiment, the depth of the embossed structure does not have to be limited to the copper layer, but can extend to the nickel layer. The microstructure preferably has a structure depth of 10 μm to 150 μm relative to the surface of the chrome layer surrounding the structure.

As already explained, thermal structure embossing or hot embossing in the context of the invention refers to a method in which a prefabricated structure on a stamp is transferred to the substrate to be embossed under the influence of heat. In the context of the invention, the structure embossing of the substrate is preferably carried out in the roll-to-roll process at embossing surface temperatures of 50 ° to 130 ° C.

In principle, the method according to the invention can be used for a large number of types of substrates. It should be emphasized, however, that the process has proven to be particularly efficient when hot stamping transfer foil. A suitable transfer film consists, for example, of thermoplastic material. The material of the transfer film can be selected, for example, from polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyester, polycarbonate, cellophane. Others too Plastics, such as bio-based plastics, for example polycactide, cellulose acetates and starch blends, can be used as the material of the transfer film. Preferred plastics are cellulose acetates, such as cellulose diacetate or cellulose triacetate. Composite materials of different foils or foil / paper are also suitable for the transfer foils. The connection of two materials to produce a composite material can be done, for example, by gluing using dispersion, LF or LH adhesives, co-extrusion or using ultrasound. The structured transfer foils can be transparent or opaque.

In the case of a transfer film, the thickness of the substrate is preferably 10 μm to 250 μm. Most preferred is a substrate thickness between 50 μm and 90 μm so that a sufficient balance between flexibility and rigidity is achieved in order to be used in the method according to the invention. To improve the rigidity, the substrate can also have a thermoreactive adhesive layer, for example made of EVA / PE.

Another embodiment of the invention provides that the substrate is guided between the surface of the embossing sleeve and the surface of a heated impression cylinder. Here, the embossing surface and the substrate lying on it are pressed against each other by at least one other roller, here a counter-pressure cylinder, similar to a counter-pressure roller, ie the substrate is pressed against the heated embossing surface and the structure of the embossing surface is embossed into the substrate. According to the invention it is provided that the impression cylinder is also heated, so that the heat in the impression cylinder is transferred into the substrate. This allows the substrate temperature to be better adjusted for the embossing process.

In the context of thermal embossing processes, counter pressure rollers with a flexible surface coating are often used. However, not every substrate to be embossed can always be efficiently processed with the same surface coating or surface hardness. Depending on the type of substrate, a different surface hardness is required for the impression cylinder or the impression roller in order to achieve an optimal result. For this reason, a further embodiment of the invention provides that the counter-pressure cylinder or the counter-pressure roller is also designed as a flexible and easily exchangeable sleeve system, the counter-pressure cylinder being designed as a counter-pressure sleeve in the form of a sleeve designed as an interchangeable unit, which against at least one other counter-pressure sleeve is designed to be exchangeable, wherein the counterpressure sleeve can be clamped for assembly on a mandrel that has been retracted into the counterpressure sleeve. Different sleeves with different surface Shore hardnesses can be provided, which can be installed in an embossing system with little effort as required in order to set the Shore hardness of the impression cylinder suitable for the embossing process, which lowers costs and increases flexibility. In the context of the method according to the invention, a further embodiment of the invention therefore provides that the hardness of the surface of the impression cylinder is set as a function of the substrate material by mounting an impression sleeve with the corresponding surface hardness.

According to a further embodiment of the invention, the counterpressure sleeve is heated via the clamping system, for example by means of a heating coil or the like that is built into the clamping mandrel.

According to a further embodiment of the invention it is provided that the substrate is heated by a temperature control device before it is guided over the embossing surface. The temperature control of the substrate can be done, for example, by a separate temperature control roller, which is arranged in the direction of travel of the substrate in front of the embossing sleeve. The substrate is preheated by means of the temperature control roller and can be brought to or near the target temperature. In this way, an embossed image can be generated with high repeat accuracy, especially at high speeds of several hundred meters per minute.

The invention further comprises a seamless embossed sleeve as described herein in a plurality of embodiments.

Furthermore, the invention comprises a system for thermal structural embossing of substrates by means of sleeve technology, comprising an embossing sleeve, in particular as described herein in a number of embodiments, in the form of a sleeve designed as an interchangeable unit, which is designed to be exchangeable for at least one other embossing sleeve, the Embossing sleeve for assembly in an embossing system can be clamped onto a mandrel inserted into the sleeve, and a counter-pressure cylinder, also in the form of a sleeve designed as an interchangeable unit, in particular as described herein, which is designed to be exchangeable for at least one other counter-pressure sleeve, the counter-pressure sleeve for Assembly can be clamped onto a mandrel that has been retracted into the counterpressure sleeve. Embossing sleeve and counterpressure sleeve are arranged in such a way that the substrate is guided between the two sleeves during embossing. The embossing sleeve and preferably also the counterpressure sleeve are heated by a heating device in the respective mandrels, that is, the heat is transferred from one mandrel via the inside of the embossing sleeve into the embossing sleeve and heat can also be transferred from the other mandrel via the inside of the counterpressure sleeve into the counterpressure sleeve be entered. The respective Mandrels in thermally conductive contact with the inside of the embossing sleeve or the counterpressure sleeve and heats the component from the inside. The system preferably also has the temperature control device described above for pre-temperature control of the substrate.

According to a further embodiment of the invention, the sleeve of the embossing sleeve and / or the counterpressure sleeve has an inner jacket, i.e. an inner surface which tapers conically in the direction from one end of the sleeve to the other end of the sleeve.

According to a further embodiment of the invention, the sleeve of the embossing sleeve and / or the counterpressure sleeve has an inner jacket, i.e. an inner surface which is cylindrical from one end of the sleeve to the other end of the sleeve.

FIGURE DESCRIPTION

Figur 1

einen Prägesleeve nach einer ersten Ausführungsform der Erfindung in perspektivischer Ansicht; und

Figur 2

schematisch den Aufbau des Prägesleeves aus Figur 1 in einer Querschnittansicht;

Figur 3

Abschnitte von Prägesleeves nach weiteren Ausführungsformen der Erfindung in Querschnittansichten;

Figur 4

eine Anlage zum thermischen Strukturprägen von Substraten nach einer weiteren Ausführungsform der Erfindung.

Further features, advantages and possible applications of the present invention can also be found in the following description of exemplary embodiments and the drawings. Show it:

Figure 1

an embossing sleeve according to a first embodiment of the invention in a perspective view; and

Figure 2

schematically the structure of the embossing sleeve Figure 1 in a cross-sectional view;

Figure 3

Sections of embossing sleeves according to further embodiments of the invention in cross-sectional views;

Figure 4

a system for thermal structure embossing of substrates according to a further embodiment of the invention.

Figure 1 shows an embossing sleeve (embossing cylinder) 1 in the form of a sleeve, ie the embossing sleeve 1 has a hollow cylindrical body which extends along an axis 2. The outer surface of the embossing sleeve 1, ie the outer jacket surface, is designed as an embossing surface 3. An embossed structure 4 is molded into the embossing surface 3 and extends over several sections of the embossing sleeve 1. For reasons of illustration, only part of the embossed structure 4 is shown. The embossed structure 4 has a number of 3-dimensional structural elements 5 molded into the embossed surface 3, for example in the form of motifs, holograms, numbers, letters or functional elements. With the exception of the embossed structure 4, the outer surface of the embossed sleeve is flat throughout and has no weld seams or the like that impair the embossed image in the substrate to be embossed. In this regard, one speaks of a seamless embossing sleeve or a seamless embossing cylinder.

The embossing sleeve is designed as an interchangeable unit and can be exchanged for other embossing sleeves in the embossing device. For assembly in an embossing system, a mandrel is pushed into the embossing sleeve designed as a sleeve (shown by the arrow) and the sleeve is clamped on this with its inner surface 6. The embossing sleeve 1 installed on the tensioning system can then revolve in the manner of a solid roller and mold the embossed image in a substrate web running on the outside of the embossing sleeve. The inner surface of the embossing sleeve 1 can taper in the direction of the axis 2 from one end of the sleeve towards the other end of the sleeve. But it can also be continuously cylindrical.

Figure 2 shows the embossed sleeve 1 Figure 1 in a cross-sectional view, ie in the viewing direction along the axis 2 (Figure 1). The representation of the cross section of the embossing sleeve in the Figure 2 is not true to scale, but is only intended to show the schematic structure of the embossing sleeve.

To produce the seamless embossing sleeve, a hollow cylindrical blank 7, i.e. also sleeve-shaped, is first provided. A coating is then built up galvanically on the lateral surface 8 of the blank 7 in several stages. First, a first cladding layer 9 made of nickel is built up on the blank 7 by electroplating. In a further step, a second cladding layer 10 made of copper is galvanically built up on the first cladding layer 9. A third galvanically built-up cladding layer 11 made of chromium completes the coating. The thickness of the first cladding layer is approximately 120-180 µm. The thickness of the second cladding layer is approximately 250-310 µm. The thickness of the third cladding layer is approximately 15-25 µm.

The introduction of the embossed structure into the surface of the embossed sleeve 1 is with reference to FIG Figure 3 described in two different variants.

Figure 3 shows in the representation a) in a cross-sectional view, similar to FIG Figure 2 , a section of the wall of an embossing sleeve 1 according to a further embodiment of the invention. The first cladding layer 9 made of nickel, the second cladding layer 10 made of copper and the third cladding layer 11 made of chromium are applied to the blank 7. An embossed structure 4 in the form of a nanostructure with structural elements 5 is molded into the surface of the chrome plating 11 by means of laser engraving. The embossed structure 4 was introduced after the third coating layer 11 made of chrome had been applied.

In the illustration b), a further embodiment of the invention is shown, in which first the first cladding layer 9 made of nickel was applied to the blank 7. The second cladding layer 10 made of copper was then applied to the first cladding layer 9 made of nickel. In a further processing step, a microstructure as an embossed structure 4 with corresponding structural elements 5 was molded into the outside of the second cladding layer 10 made of copper. In a further process step, the chrome plating 11 was applied to the outer surface of the second cladding layer 10 made of copper. The embossed structure 4 introduced into the second cladding layer 10 made of copper with the corresponding structural elements 5 is also formed on the outer surface of the third cladding layer 11 made of chrome after the protective chrome plating has been applied.

The embossed structures in the Figures 3a and 3b can also be combined as desired, so nano- and microstructures can be formed on the embossing sleeve 1.

Figure 4 shows schematically a system with a sleeve-like embossing sleeve 1 and a counter-pressure cylinder in the form of a likewise sleeve-like counter-pressure sleeve 12. The embossing sleeve 1 and the counter-pressure sleeve 12 are clamped on a mandrel 13, 14 retracted into the respective sleeve and rotate in the circumferential direction. The mandrels are only indicated by a cross and have heating devices (not shown) by means of which the respective sleeve 1, 12 is heated from the inside.

The system further comprises a temperature control roller 15 for preheating a substrate 16 in web form to be embossed in the system. The illustration shows only part of the system. The substrate web 16 is unwound from a roll (not shown) and initially guided over the temperature control roller 15. The substrate is preheated there. The substrate is then passed onto the embossing surface 3 of the embossing sleeve and between the surfaces of the embossing sleeve 1 and counterpressure sleeve 12. There the substrate web 16 is embossed under the influence of heat and counter pressure. After the embossing, the substrate is led away from the embossing sleeve 1 and can be wound up again on a roll.

If the embossed image is to be changed, the embossed sleeve 1 can be removed from the mandrel 13 and replaced by another embossed sleeve with a different embossed image. Similarly, the counterpressure sleeve 12 can be exchanged for another counterpressure sleeve with a different surface hardness if a different surface hardness is necessary for the impression cylinder.

List of reference symbols

1

Embossing sleeve (embossing cylinder)

2

axis

3

Embossing surface

4th

Embossing structure

5

Structural elements

6th

inner surface

7th

blank

8th

Outer surface blank

9

first coat layer (nickel)

10

second cladding layer (copper)

11

third coat layer (chrome)

12th

Impression cylinder (impression sleeve)

13th

Mandrel for embossing sleeve

14th

Mandrel for impression cylinder

15th

Tempering roller

16

Substrate

Claims (16)

Method for thermal structure embossing of substrates with an embossing cylinder, the substrate (16) being guided along a heated embossing surface (3) of the embossing cylinder during embossing in order to form the structure of an embossing structure (4) molded into the embossing surface in the substrate (16) ,
characterized in that the embossing cylinder is an embossing sleeve (1) in the form of a sleeve designed as an interchangeable unit, which is designed to be exchangeable for at least one other embossing sleeve, the embossing sleeve being able to be clamped onto a mandrel (13) inserted into the sleeve for assembly in an embossing system ; and that the embossing surface (3) of the embossing sleeve (3) is heated via the mandrel (13). Method according to claim 1, wherein the embossing sleeve (1) has an inner jacket which tapers conically or is cylindrical in the direction from one end of the embossing sleeve (1) to the other end of the embossing sleeve. Method according to claim 1 or 2, wherein the embossed sleeve (1) and / or the embossed structure (4) are seamless. Method according to one of the preceding claims, wherein the embossing sleeve (1) comprises a hollow cylindrical body (7), the outer jacket surface (8) of which is provided with a coating into which the embossing structure (4) is molded, the coating a first coating layer (9) made of nickel with a thickness of 120-180 µm, a second cladding layer (10) made of copper with a thickness of 250-310 μm, and has a third cladding layer (11) in the form of a chrome layer with a thickness of 15-25 µm. Method according to one of the preceding claims, wherein the embossed structure (4) is a nanostructure, preferably with a structure depth of 100 nm to 500 nm, more preferably 100 nm to 200 nm, particularly preferably 120 nm to 150 nm. Method according to one of the preceding claims, wherein the embossed structure (4) is a microstructure, preferably with a structure depth of 10 µm to 150 µm. Method according to one of the preceding claims, wherein the substrate (16) is guided between the surface of the embossing sleeve (1) and the surface of a heated impression cylinder (12). The method according to claim 7, wherein the counterpressure cylinder is designed as a counterpressure sleeve (12) in the form of a sleeve designed as an interchangeable unit, which is designed to be exchangeable for at least one other counterpressure sleeve, the counterpressure sleeve for assembly on a clamping system (14) retracted into the counterpressure sleeve, like a mandrel, can be clamped. Method according to claim 8, wherein the counterpressure sleeve (12) is heated via the tensioning system (14). Method according to one of claims 7 to 9, wherein the hardness of the surface of the impression cylinder (12) is adjusted as a function of the substrate material by a counter pressure sleeve with the corresponding surface hardness is mounted. Method according to one of claims 7 to 10, wherein the counterpressure sleeve (12) has an inner jacket which tapers conically or is cylindrical in the direction from one end of the counterpressure sleeve (12) to the other end of the counterpressure sleeve (12). Method according to one of the preceding claims, wherein the substrate (16) is heated by a temperature control device (15) before it is guided over the embossing surface (3). Method according to claim 12, wherein the substrate (16) is heated via a temperature control roller (15). Seamless embossing sleeve (1) in the form of a sleeve for thermal structure embossing of substrates, the embossing sleeve comprising a hollow cylindrical body (7), the outer surface (8) of which is provided with a coating into which an embossing structure (4) is molded, the Coating a first coating layer (9) made of nickel with a thickness of 120-180 µm, a second cladding layer (10) made of copper with a thickness of 250-310 μm, and has a third cladding layer (11) in the form of a chrome layer with a thickness of 15-25 µm. System for thermal structure embossing of substrates in which the substrate (16) during embossing is guided along a heated embossing surface (3) of an embossing cylinder in order to form the structure of an embossing structure (4) molded into the embossing surface, comprising a Embossing cylinder, which is designed as an embossing sleeve (1) in the form of a sleeve designed as an interchangeable unit, which is designed to be exchangeable for at least one other embossing sleeve, wherein the embossing sleeve (1) can be clamped onto a mandrel (13) inserted into the sleeve, and wherein the mandrel (13) has a heating device in order to introduce heat into the embossing sleeve (1). System according to claim 15, wherein a preferably heated counterpressure roller is provided, which is designed as a counterpressure sleeve (12) in the form of a sleeve designed as an interchangeable unit, which is designed to be exchangeable for at least one other counterpressure sleeve (12), the counterpressure sleeve (12) for Can be mounted on a clamping system (14), such as a mandrel, retracted into the counterpressure sleeve.

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