Method for transferring an embossed structure to a surface of a coating device and composite structure usable as an embossing die

文档序号：975897 发布日期：2020-11-03 浏览：13次中文

阅读说明：本技术 将压纹结构转印到涂覆装置表面的方法和可用作压纹模头的复合结构 (Method for transferring an embossed structure to a surface of a coating device and composite structure usable as an embossing die ) 是由 J-B·库斯 S·皮昂泰克 J·埃克斯纳 B·克莱恩-布莱 R·范德阿 M·洛伦兹 F· 于 2019-03-28 设计创作，主要内容包括：本发明涉及一种将压纹结构转印到涂料组合物(B2a)的表面上的方法,其包括步骤(1-i)和(2-i)或(1-ii)和(2-ii)以及步骤(3)和任选的(4),其中使用用作压纹工具(P2)的压纹模头(p2)并且由基材(F1)和至少部分压纹且至少部分固化的涂层(B1)组成的复合结构(F1B1)来实施步骤(1-i)和(2-i)或(1-ii)和(2-ii),并且用于制备复合结构(F1B1)的(B1)的涂料组合物(B1a)是具有限定组成的可辐射固化的涂料组合物,还涉及复合结构(F1B1)以及复合结构(F1B1)作为压纹工具(P2)的压纹模头(p2)以将压纹结构转印到涂料组合物(B2a)的至少一部分的表面的用途。(The present invention relates to a method for transferring an embossed structure onto the surface of a coating composition (B2a), comprising steps (1-i) and (2-i) or (1-ii) and (2-ii) and step (3) and optionally (4), wherein steps (1-i) and (2-i) or (1-ii) and (2-ii) are carried out using an embossing die (P2) serving as an embossing tool (P2) and a composite structure (F1B1) consisting of a substrate (F1) and an at least partially embossed and at least partially cured coating (B1), and the coating composition (B1a) used for preparing (B1) of the composite structure (F1B1) is a radiation curable coating composition having a defined composition, and to the use of the composite structure (F1B1) and the composite structure (F1B1) as an embossing die (P2) of an embossing tool (P2) for transferring the embossed structure onto at least a portion of the surface of the embossed structure (B2a) to transfer the embossed structure (B a) to the coating composition (F1B 3625) .)

1. A method for transferring an embossed structure onto at least a part of the surface of a coating composition (B2a), comprising at least steps (1-i) and (2-i) or (1-ii) and (2-ii) and at least step (3) and optionally (4), in particular

(1-i) applying the coating composition (B2a) to at least a part of the surface of the substrate (F2), and

(2-i) at least partially embossing the coating composition (B2a) applied at least partially onto the surface of the substrate (F2) by means of at least one embossing tool (P2) comprising at least one embossing die (P2), wherein the embossing die (P2) comprises a composite (B1F1) consisting of the substrate (F1) and an at least partially embossed and at least partially cured coating (B1), so that after at least partial embossing a composite (F2B2aB1F1) is obtained,

(1-ii) applying a coating composition (B2a) onto at least a part of the at least partially embossed surface of the composite (B1F1) to obtain a composite (B2aB1F1), wherein the composite (B1F1) is used as an embossing die (P2) of an embossing tool (P2) and consists of a substrate (F1) and an at least partially embossed and at least partially cured coating (B1), and

(2-ii) applying a substrate (F2) to at least a part of the surface formed by (B2a) of the complex (B2aB1F1) to obtain a complex (F2B2aB1F1),

and

(3) at least partially curing the coating composition (B2a) in the resulting composite (F2B2aB1F1) to obtain a composite (F2B 1F1), wherein the coating composition (B2a) is in contact with the portion of composite (B1F1) that acts as the embossing die (p2) in the composite (F2B2aB1F1) throughout the at least partial curing, and

(4) optionally removing the complex (F2B2) from the complex (B1F1) used as embossing die (p2) (F2B2B1F1),

wherein the coating composition (B1a) used for preparing the coating (B1) of the composite (B1F1) used as embossing die (p2) is a radiation-curable coating composition,

wherein the coating composition (B1a) comprises:

at least one component (a) in an amount of 40 to 95% by weight,

as component (b) at least one additive in an amount of 0.01 to 5% by weight,

at least one photoinitiator as component (c) in an amount of from 0.01 to 15% by weight, and

at least one component (d) in an amount of from 0 to 45% by weight, which contains at least one carbon double bond,

wherein (i) each of components (a), (B), (c), and (d) are different from each other, (ii) each of said amounts of components (a), (B), (c), and (d) is based on the total weight of coating composition (B1a), and (iii) the amounts of all components present in coating composition (B1a) add up to 100 wt.%,

and wherein component (a) comprises at least 3 structural units of formula (I), each different or at least partially identical to each other:

wherein:

radical R¹In each case independently of one another is C₂-C₈An alkylene group or a substituted alkylene group,

radical R²In each case independently of one another, H or methyl, and

the parameters m are each, independently of one another, an integer parameter of from 1 to 15, with the proviso that in at least one structural unit of the formula (I) of the component (a) the parameter m is at least 2.

2. The method according to claim 1, wherein the substrate (F2) is a preferably moving film web.

3. The method according to claim 1 or 2, wherein the microstructures and/or nanostructures are transferred as embossed structures to the coating composition (B2a) by step (2-i) or by steps (1-ii) and (2-ii).

4. The method according to any one of the preceding claims, wherein the embossing die (P2) of the embossing tool (P2) used in steps (2-i) and (1-ii) is reusable and can be repeatedly used to transfer at least one embossed structure when carrying out step (4) of the method.

5. The process according to any one of the preceding claims, wherein the composite (B1F1) used as embossing die (p2) in steps (2-i) and (1-ii) is a composite consisting of a film web (F1) and a coating (B1) applied thereon and at least partially embossed and at least partially cured.

6. The method of any preceding claim, wherein:

in carrying out step (2-i), the composite (B1F1) used as the embossing die (P2) in step (2-i) is guided via a first roller used as the embossing tool (P2), and the composite (F2B2a) is guided via a second roller opposite to and counter-rotating or co-rotating with the first roller, and

after applying the coating composition (B2a) onto at least a part of its at least partially embossed surface to obtain a composite (B2aB1F1), during the implementation of step (2-ii), the composite (B1F1) used in step (1-ii) as embossing die (P2) is guided via a first roller used as embossing tool (P2), and the substrate (F2) used in step (2-ii) is guided via a second roller opposite and counter-rotating or co-rotating to the first roller.

7. The method of claim 6, wherein:

the at least partial embossing of step (2-i) is carried out at the level of a nip formed by two counter-rotating or co-rotating opposing rolls with the at least partially embossed coating (B1) of the composite (B1F1) facing the coating composition (B2a) of the composite (F2B2a), and

the at least partial embossing of step (2-ii) is carried out at the level of a nip formed by two opposite rolls rotating counter-or co-rotating with each other, with the coating composition (B2a) of the composite (B2aB1F1) facing the substrate (F2).

8. The process according to any one of the preceding claims, wherein the solids content of the coating composition (B1a) is ≥ 90% by weight, based on the total weight of the coating composition (B1 a).

9. The process according to any one of the preceding claims, wherein in each of the at least 3 structural units of formula (I) of component (a) the parameter m is at least 2.

10. The process according to any one of the preceding claims, wherein the ether segment- [ O-R ] present in the structural unit of formula (I) of component (a)¹]_m-a fraction of at least 35 wt. -%, based on the total weight of component (a).

11. The method according to any one of the preceding claims, wherein the composite (F1B1) used as embossing die (P2) of the embossing tool (P2) and consisting of a substrate (F1) and an at least partially embossed and at least partially cured coating (B1) is obtainable at least by steps (5) to (8), in particular by the steps of:

(5) applying a radiation curable coating composition (B1a) to at least a portion of the surface of a substrate (F1),

(6) at least partially embossing the coating composition (B1a) applied at least partially to the surface of the substrate (F1) by means of at least one embossing tool (P1) having at least one embossing die (P1),

(7) at least partially curing the at least partially embossed coating composition (B1a) applied to at least a part of the surface of the substrate (F1) by radiation curing, thereby obtaining a composite (F1B1) consisting of the substrate (F1) and the at least partially embossed and at least partially cured coating (B1), wherein the coating composition (B1a) is in contact with at least one embossing die (P1) of at least one embossing tool (P1) throughout the at least partially curing, and

(8) the composite (F1B1) was removed from the embossing tool (P1).

12. A composite (F1B1) consisting of a substrate (F1) and an at least partially embossed and at least partially cured coating (B1) and preparable by at least partially curing a cured coating composition (B1a) applied to at least a part of the surface of the substrate (F1) and at least partially embossed by radiation curing, wherein the coating composition (B1a) is a radiation-curable coating composition,

wherein the coating composition (B1a) comprises:

at least one component (a) in an amount of 40 to 95% by weight,

as component (b) at least one additive in an amount of 0.01 to 5% by weight,

at least one photoinitiator as component (c) in an amount of from 0.01 to 15% by weight, and

at least one component (d) in an amount of from 0 to 45% by weight, which contains at least one carbon double bond,

and wherein component (a) comprises at least 3 structural units of formula (I), each different or at least partially identical to each other:

wherein:

radical R¹In each case independently of one another is C₂-C₈An alkylene group or a substituted alkylene group,

radical R²In each case independently of one another, H or methyl, and

13. The complex (F1B1) according to claim 12, wherein the complex is obtainable by carrying out steps (5) to (8) of the method according to claim 11.

14. The composite according to claim 12 or 13, wherein the substrate (F1) is a preferably moving film web.

15. Use of the composite (F1B1) according to any one of claims 12 to 14 as an embossing die (P2) of an embossing tool (P2) to transfer an embossed structure onto at least part of the surface of a coating composition (B2a) or onto at least part of the surface of a coating composition (B2a) applied at least to a substrate (F2).

Prior Art

In many applications in industry, it is now common to provide structures on the surface of workpieces whose structural features are in the micrometer range or even in the nanometer range. The structures are also referred to as microstructures (structures with features in the micrometer range) or nanostructures (structures with features in the nanometer range). The structures are used, for example, to influence the optical, biomimetic and/or tactile quality of the material surface. This structure is also referred to as an embossing or an embossed structure.

Here, one common method is to transfer these structures into a coating. Here, the transfer of the structure to the coating material is generally effected by an embossing operation, in which a die comprising the microstructures and/or nanostructures to be formed on the embossing surface or transfer surface is brought into contact with the coating material in negative form and is embossed into the coating material. The coating is then typically cured in place in order to permanently form and hold the structure on the surface of the workpiece.

WO90/15673a1 describes a method in which a radiation-curable coating is applied to a film or embossing die having the desired negative-type embossing structure, and then an embossing tool is printed onto the foil, onto the foil provided with the coating or onto the embossing tool provided with the coating. Curing is carried out while the radiation curable coating is still located between the foil and the embossing tool, and then after removal of the tool, a film provided with the radiation curable coating is obtained, which contains the desired positive features. European patent EP1135267B1 also describes such a process in which a curable coating is applied to the surface of a substrate for decoration and a corresponding embossing die with a negative pattern is pressed into the uncured coating. Thereafter, the coating is cured, followed by removal of the embossing die. EP3178653a1 discloses a replica cast article for curable systems comprising a flexible fabric having a textured surface. The fabric may have a polymer layer, which may be prepared by using monofunctional and multifunctional acrylates.

Us patent 9,778,564B2 discloses an imprint material comprising a component which must contain (meth) acrylamide structural units, and a further component having 2 to 6 polymerizable groups, which component also has oxyalkylene units. After the material is applied to a substrate, the film obtained therefrom may be provided with a pattern during its curing by UV radiation using a nickel embossing tool.

US2007/0204953a1 discloses a method of patterning an adhesive resin which provides, in sequence, applying a curable layer of adhesive resin to a substrate, applying a structured pattern to the layer, and subsequently curing the layer to provide a substrate provided with a cured adhesive resin comprising the desired pattern.

WO2015/154866a1 relates to a method of preparing a substrate having a structured surface. In this case, a first UV-curable coating is first applied to the substrate and cured. A second UV cured coating was then applied over the cured coating as an embossing varnish, embossed to produce microstructures, and subsequently cured.

DE102007062123a1 describes a process in which an embossing varnish, such as a UV-crosslinkable embossing varnish, is applied to a carrier film, the embossing varnish is structured in the micrometer range, and the embossing varnish applied to the film is cured to give an embossed film, and the microstructure is subsequently shaped by depositing a metal on the embossed surface, in other words by metallizing the film. However, a disadvantage of such shaping by subsequent metallization is that the resulting shaping quality is undesirably reduced.

Finally, EP2146805B1 describes a method for producing a material with a textured surface. The method includes providing a substrate having a curable coating, contacting the coating with a texturing medium for embossing, and then curing and removing the coating embossed in this manner from the texturing medium. The texturing medium comprises a surface layer comprising 20-50% of an acrylic oligomer, 15-35% of a monofunctional monomer and 20-50% of a multifunctional monomer. WO2016/090395A1 and ACS Nano Journal, 2016, 10, pages 4926-4941 describe similar processes, in each case specifically teaching that, for the preparation of the surface layer of the textured medium, mostly triethoxylated trimethylolpropane triacrylate (TMP (EO)₃TA) to produce a relatively hard die for texturing the media. Furthermore, according to WO2016/090395a1, the coating composition used for preparing the surface layer must also comprise structural units having at least two thiol groups, for example trimethylolpropane tris (3-mercaptopropionate). However, the use of such thiols in corresponding coating compositions is often disadvantageous, because the compositions do not always have sufficient stability on storage, and because coatings prepared therefrom lack sufficient weathering stability. Another factor is the unpleasant smell resulting from the use of mercaptans, which is of course also undesirable.

However, the embossing methods known from the prior art, such as in particular the methods described in EP2146805B1, WO2016/090395a1 and ACS Nano Journal, 2016, 10, page 4926-4941, do not always transfer the embossing sufficiently, in particular in the micrometer range and/or nanometer range, i.e. the microstructures and/or nanostructures, and in particular in the case of such transfer, do not reduce the precision of the shaping to an unacceptable degree. At the same time, embossing is not always sufficiently replicated.

Therefore, there is a need for an embossing method that does not have the above-mentioned disadvantages.

Problem(s)

The problem underlying the present invention is therefore to provide a method for transferring an embossed structure to a coating composition, a substrate comprising the coating composition, more particularly a substrate which allows the transfer of corresponding microstructures and/or nanostructures and which allows sufficient shaping accuracy in the transfer of the embossed structure such that the embossing is not accompanied by any loss of modulation depth, and in particular enables the production of a very large number of reusable embossing dies for transferring the embossed structure, and/or a method which can be carried out using such embossing dies. At the same time, the embossed structure to be transferred can be highly reproduced without a process characterized by any disadvantages, which are brought about in particular by undesirable or insufficient properties of the coatings and coating compositions used, such as insufficient adhesion.

Solution scheme

This problem is solved by the subject matter claimed in this patent claim and by preferred embodiments of this subject matter described in the following description.

Accordingly, a first subject of the present invention is a process for transferring an embossed structure onto at least a portion of the surface of a coating composition (B2a), comprising at least steps (1-i) and (2-i) or (1-ii) and (2-ii) and at least step (3) and optionally (4), in particular

(1-i) applying the coating composition (B2a) to at least a part of the surface of the substrate (F2), and

(2-ii) applying a substrate (F2) to at least a part of the surface formed by (B2a) of the complex (B2aB1F1) to obtain a complex (F2B2aB1F1),

and

(4) optionally removing the complex (F2B2) from the complex (B1F1) used as embossing die (p2) (F2B2B1F1),

wherein the coating composition (B1a) used for preparing the coating (B1) of the composite (B1F1) used as embossing die (p2) is a radiation-curable coating composition,

wherein the coating composition (B1a) comprises:

at least one component (a) in an amount of 40 to 95% by weight,

as component (b) at least one additive in an amount of 0.01 to 5% by weight,

at least one photoinitiator as component (c) in an amount of from 0.01 to 15% by weight, and

at least one component (d) in an amount of from 0 to 45% by weight, which contains at least one carbon double bond,

and wherein component (a) comprises at least 3 structural units of formula (I), each different or at least partially identical to each other:

wherein:

radical R¹In each case independently of one another is C₂-C₈An alkylene group or a substituted alkylene group,

radical R²In each case independently of one another, H or methyl, and

Preferably, the parameter m in the at least 3 structural units of the formula (I) which are different from one another or at least partly identical in component (a) of the coating composition (B1a) is in each case at least 2.

It was surprisingly found that the process of the present invention enables the transfer of embossed structures, more particularly micro-and/or nano-structures, onto the coating composition (B2a) to be embossed with very high shaping accuracy, such that there is no loss of modulation depth during embossing, wherein shaping is more particularly performed with high accuracy of 10nm to 1000 μm structure width and 0.1nm to 1000 μm structure depth. In this connection, it was found particularly surprisingly that the process according to the invention makes it possible to transfer embossed structures with a composite (F1B1) which can be obtained by applying a radiation-curable coating composition (B1a) to a preferably moving substrate (F1) with a very high shaping accuracy and a high level of replication success, and which is used as an embossing die (P2) of an embossing tool (P2).

It was further surprisingly found that the process of the invention can be applied so advantageously, since the coating (B1) of the compound (F1B1) used is distinguished by a high double bond conversion, which coating can be obtained by applying a radiation-curable coating composition (B1a) to a preferably moving substrate (F1). Thus, in optional step (4) of the process of the invention, an efficient separation can be achieved, in particular between the composite (F2B2) and the embossing tool (P2). Furthermore, it was surprisingly found that the process of the invention can be applied so advantageously, since the coating (B1) on the substrate (F1) is characterized by very good adhesion, and also for this reason the corresponding composite (F1B1) can be used very effectively as embossing die (p 2).

It was further surprisingly found that the composite (F1B1) which can be used as embossing die (P2) of the embossing tool (P2) in the process of the present invention can be used again for transferring embossed structures, for example microstructures and/or nanostructures, in particular in the form of a continuous embossing die, which is advantageous for economic reasons. Furthermore, surprisingly, the composite (F1B1), preferably in the form of a continuous embossing die (p2), is not only reusable and thus multi-utilizable, but can also be produced inexpensively and rapidly on a large industrial scale.

Thus, a further subject of the invention is also a composite (F1B1) which consists of a substrate (F1) and an at least partially embossed and at least partially cured coating (B1) and can be prepared by at least partially curing by radiation curing a coating composition (B1a) which is applied to at least a part of the surface of the substrate (F1) and is at least partially embossed, wherein the coating composition (B1a) is a radiation-curable coating composition,

wherein the coating composition (B1a) comprises:

at least one component (a) in an amount of 40 to 95% by weight,

as component (b) at least one additive in an amount of 0.01 to 5% by weight,

at least one photoinitiator as component (c) in an amount of from 0.01 to 15% by weight, and

at least one component (d) in an amount of from 0 to 45% by weight, which contains at least one carbon double bond,

wherein (i) each of components (a), (B), (c), and (d) are different from each other, (ii) each of said amounts of components (a), (B), (c), and (d) are based on the total weight of coating composition (B1a), and (iii) the amounts of all components present in coating composition (B1a) add up to 100 wt.%,

and wherein component (a) comprises at least 3 structural units of formula (I), each different or at least partially identical to each other:

wherein:

radical R¹In each case independently of one another is C₂-C₈An alkylene group or a substituted alkylene group,

radical R²In each case independently of one another, H or methyl, and

Preferably, the complex (F1B1) is obtainable by carrying out the process steps (5) to (8), which will be described in more detail below.

It was surprisingly found that the at least partially embossed composition (F1B1) of the present invention can be used not only as a reusable embossing die (P2), preferably as a reusable continuous embossing die (P2), in an embossing process, e.g. the process of the present invention, but also due to the components present in the radiation curable coating composition (B1a) used for preparing the composite, a very efficient separation can be achieved between the composite (F1B1) used as embossing die (P2) in the embossing tool (P2) and the embossed coating (B2) and/or a corresponding composite comprising the embossed coating, e.g. coating (B2), e.g. composite (F2B2), especially when carrying out the process of the present invention and in the optional step (4) therein. Furthermore, it has surprisingly been found that the coating (B1) of the compound (F1B1) used, which can be obtained by applying the radiation-curable coating composition (B1a) to a substrate (F1), is advantageously characterized by a high double bond conversion, for example a double bond conversion of ≥ 90%. In particular, it was further found that, especially when traversing the method steps (5) to (8) for preparing the composite (F1B1), the embossed structure of the coating (B1) can be obtained with high shaping accuracy and high replication success rate.

Furthermore, another subject of the present invention is the use of the composite (F1B1) according to the invention as an embossing die (P2) of an embossing tool (P2) for transferring an embossed structure onto at least a part of the surface of a coating composition (B2a) or at least a part of the surface of a coating composition (B2a) applied to a substrate (F2).

Description of the invention

In the sense of the present invention, the term "comprising" preferably has the definition of "consisting of … …" in the case of the coating compositions used according to the invention, for example in the case of the coating composition (B1a) and the process according to the invention and the process steps thereof. For example, for the coating composition (B1a) used according to the invention, in addition to components (a) and (B) and (c) and optionally (d), the composition may furthermore comprise one or more further components described below and optionally present in the coating composition (B1a) used according to the invention. All components may each be present in their preferred embodiments as described hereinafter. For the process of the invention, it may have further optional process steps, for example steps (5) to (8), in addition to steps (1-i) and (2-i) or (1-ii) and (2-ii) and (3) and optionally (4).

The method of transferring an embossed structure of the present invention comprises at least steps (1-i) and (2-i) or (1-ii) and (2-ii) and (3) and optionally (4)

As mentioned above, a first subject of the present invention is the method of transferring an embossed structure onto at least a portion of the surface of the coating composition (B2a) according to the present invention. FIG. 1 illustrates steps (1-i) and (2-i) and (3) and optionally (4) of the process of the invention, as will be seen from the description of the figure below.

The process of the invention is preferably a continuous process.

According to method step (2-i), the embossed structure is transferred or retained by at least partially embossing the coating composition (B2a) applied at least partially onto the surface of the substrate (F2). Another possibility is to carry out the transfer by process steps (1-ii) and (2-ii). The term "embossing" means coating a coating composition (B2a), optionally as part of a composite (F2B2a), with an embossed structure on at least a portion of its surface. In this case, at least certain regions of the coating composition (B2a) are decorated with an embossed structure. Preferably, the entire surface of the coating composition (B2a), optionally as part of the composite (F2B2a), is decorated with an embossed structure. Similar remarks apply in respect of the term "embossing" as used for the embossing die (p2), the at least partially embossed composite (F1B1) consisting of a substrate (F1) and an at least partially embossed and at least partially cured coating (B1) and which can be prepared according to the following steps (5) to (8).

The embossed structures of the composites (F1B1), (F2B2a) and (F2B2) are preferably and in each case independently of one another based on a repeating and/or regularly arranged pattern. In each case, the structure may be a continuous embossed structure, for example a continuous groove structure, or a plurality of preferably repeated individual embossed structures. In this case, the respective individual embossing structure can in turn preferably be based on a groove structure with more or less pronounced ridges (embossing ridges) which define the embossing height of the embossing structure. Depending on the respective geometry of the ridges of the preferably repeating individual embossed structures, the plan view may show a plurality of preferably repeating individual embossed structures, each of which is different, for example preferably a serpentine, zigzag, hexagonal, rhomboid, parallelogram, honeycomb, circular, dot-like, star, rope, net, polygonal, preferably triangular, quadrangular, more preferably rectangular and square, pentagonal, hexagonal, heptagonal and octagonal, linear, elliptical, oval and lattice-like pattern, wherein at least two patterns may also be superimposed on each other. The ridges of the individual embossed structures may also have a curvature, i.e. a convex and/or concave structure.

Each embossed structure may be described by its width (e.g. the width of the ridges), in other words by its structure width, and by its embossing height, in other words by its structure height (or structure depth). The structure width, e.g. the width of the ridges, may have a length of at most 1 cm, but preferably 10nm to 1 mm. The structure height is preferably 0.1nm to 1 mm. Preferably, however, each embossed structure represents a microstructure and/or a nanostructure. Here, a microstructure is a structure having features in the micrometer range, both in terms of structure width and structure height. Here, a nanostructure is a structure having features in the nanometer range, both in terms of structure width and structure height. Here, microstructures and nanostructures are structures having a structure width in the nanometer range and a structure height in the micrometer range, and vice versa. Here, the terms "structure height" and "structure depth" are interchangeable.

The structure width of each embossed structure is preferably from 10nm to 500 μm, more preferably from 25nm to 400 μm, very preferably from 50nm to 250 μm, more particularly from 100nm to 100 μm. The structure height of each embossed structure is preferably from 10nm to 500 μm, more preferably from 25nm to 400 μm, very preferably from 50nm to 300 μm, more particularly from 100nm to 200 μm. The same is true for the embossed structures of composite (F1B1) and composite (F2B 2).

Here, the structure width and the structure height of each embossed structure are determined by mechanical scanning of the surface. In this case, the embossing height is measured at not less than 10 points in a line, which are evenly distributed over the web width of the sample, and care is taken to ensure that the scanning instrument does not compress the embossed structure. The determination of the structure height represents the determination of the shaping accuracy and is done by means of a scanning force microscope according to the method described below.

Alternative (i) comprising steps (1-i) and (2-i)

According to alternative (i), the process of the invention comprises at least steps (1-i), (2-i) and (3) and optionally (4).

Step (1-i)

Step (1-i) of the inventive method provides for applying the coating composition (B2a) to at least a portion of the surface of the substrate (F2). The substrate (F2) represents a support material for the coating composition (B2a) or coating (B2) to be applied thereto.

The substrate (F2) or, if a coated substrate is used, the layer located on the surface of the substrate (F2) is preferably composed of at least one thermoplastic polymer, more particularly selected from the group consisting of poly (methyl (meth) acrylate, poly (butyl (meth) acrylate), polyethylene terephthalate, polybutylene terephthalate, polyvinylidene fluoride, polyvinyl chloride, polyesters, including polycarbonate and polyvinyl acetate, preferably polyesters such as PBT and PET, polyamides, polyolefins such as polyethylene, polypropylene, polystyrene and polybutadiene, polyacrylonitrile, polyacetal, polyacrylonitrile-ethylene-propylene-diene-styrene copolymer (A-EPDM), polyetherimide, phenolic resins, urea resins, melamine resins, alkyd resins, epoxy resins, polyurethanes, including TPU, polyetherketone, polyphenylene sulfide, polyethers, polyvinyl alcohol and mixtures thereof. Particularly preferred substrates or layers on their surface are polyolefins, such as PP (polypropylene), which may be isotactic, syndiotactic or atactic and may be non-oriented or oriented by mono-or biaxial stretching, SAN (styrene-acrylonitrile copolymer), PC (polycarbonate), PMMA (polymethyl methacrylate), PBT (polybutylene terephthalate), PA (polyamide), ASA (acrylonitrile-styrene-acrylate copolymer) and ABS (acrylonitrile-butadiene-styrene copolymer), and physical mixtures (blends) thereof. Particularly preferred are PP, SAN, ABS, ASA and blends of ABS or ASA with PA or PBT or PC. Particularly preferred are PET, PBT, PP, PE and Polymethylmethacrylate (PMMA) or impact modified PMMA. Particularly preferred is polyester, most preferably PET, as the material for the substrate (F2). Alternatively, the substrate (F2) itself, optionally despite the application thereon of a layer of at least one of the aforementioned polymers, may be made of a different material, such as glass, ceramic, metal, paper and/or fabric. In this case, the substrate (F2) is preferably a board and can be used, for example, in a roll-to-board embossing apparatus.

The thickness of the substrate (F2) is preferably 2 μm to 5 mm. Particularly preferred are layer thicknesses of from 25 to 1000. mu.m, more particularly from 50 to 300. mu.m.

The substrate (F2) is preferably a film, more preferably a film web, very preferably a continuous film web. In this case, the substrate (F2) may preferably be used in a roll-to-roll embossing apparatus.

In the sense of the present invention, the term "continuous film" or "continuous web" preferably refers to a film having a length of 100m to 10 km.

When carrying out step (1-i) (preferably also when carrying out steps (2-i), (3) and (4) of the process, and also when carrying out process steps (1-ii), (2-ii), (3) and (4) of alternative (ii)), the substrate (F2) is preferably a moving, and therefore moving, substrate. During the execution of steps (1-i) and (2-ii), the substrate (F2) is preferably moved by means of a conveying device such as a conveyor belt. Accordingly, the respective apparatuses for carrying out steps (1-i) and (2-ii) preferably comprise the conveying apparatus. The corresponding apparatus for carrying out step (1-i) further comprises means for applying a preferably radiation-curable coating composition (B2a) onto at least a part of the surface of the substrate (F2). Similar comments apply to the corresponding apparatus for carrying out step (2-ii).

Step (2-i)

Step (2-i) of the process of the invention provides for at least partially embossing a coating composition (B2a) applied at least partially to the surface of a substrate (F2) by means of at least one embossing tool (P2) comprising at least one embossing die (P2), the embossing die (P2) comprising a composite (B1F1) consisting of a substrate (F1) and an at least partially embossed and at least partially cured coating (B1), and the at least partially embossed product being the composite (F2B2aB1F 1). During the implementation of step (2-i), an embossing tool (P2) comprising an embossing die (P2) is preferably pressed at least partially onto the applied coating composition (B2 a).

The embossing die (P2) of the embossing tool (P2) used in step (2-i) is preferably reusable and reusable for transferring at least one embossed structure, preferably in the process of the invention, when the latter must comprise step (4). Step (2-i) preferably transfers the microstructures and/or nanostructures as embossed structures onto the coating composition (B2 a).

The embossing die (p2), in other words the compound (F1B1), preferably comprises a film web (F1) comprising an at least partially embossed and at least partially cured coating (B1). Particularly preferably, the substrate (F1) is a continuous film web comprising an at least partially embossed and at least partially cured coating (B1), thereby making the composite (F1B1) used as embossing die (p2) a continuous embossing die, especially when the substrate (F2) is also a continuous film web.

At least one embossing die (P2) for the at least partially embossed embossing tool (P2) according to step (2-i) has a "negative-type structure" ("negative shape"), i.e. a mirror image of the embossing structure possessed by the composite (F2B2) obtained after carrying out optional step (4) of the process of the invention and consisting of the substrate (F2) and the at least partially embossed and fully cured coating (B2), and a mirror image of the embossing structure of the embossing die (P1) of the embossing tool (P1).

A corresponding apparatus for carrying out step (2-i) comprises means for at least partially embossing the coating composition (B2a) applied at least partially to the surface of the substrate (F2) by means of at least one embossing tool (P2). Furthermore, the apparatus used preferably has a device for pressing (P2) onto the substrate (F2), preferably used as a continuous film web, after the radiation-curable coating composition (B2a) has been applied to (F2), which device is preferably located downstream of the device for applying the radiation-curable coating composition (B2a), viewed in the transport direction of the substrate (F2).

At least partial embossing according to step (2-i) of the method according to the invention is carried out by means of an embossing tool (P2). (P2) may preferably be an embossing calender, which preferably comprises a grid application mechanism, more preferably a grid roller mechanism. The calender has counter-rotating or co-rotating rolls, preferably arranged one above the other at intervals in the height direction, and the compound (F2B2a) to be provided with an embossed structure is supplied to the rolls and passed through the nip formed, wherein the nip width is variably adjusted. Here, the grid roller mechanism preferably comprises a first roller, for example a metal roller, for example a steel roller or a nickel roller, or a quartz-based roller or a roller coated with at least one plastic. The first roller functions as an embossing roller (press roller). Here, the grid roller mechanism preferably includes a second roller (pressing roller or pressure roller). Here, the first roller serves as an embossing tool (P2) and comprises the negative of the embossing structure to be embossed into the surface of the complex (F2B2 a). For this purpose, the embossing tool (P2) is provided with a compound (F1B1) representing the negative type as an embossing die (P2). -generating a negative version of the embossed structure on the embossing tool (P2) by methods conventional and known to the person skilled in the art; depending on the structure and materials, particular methods may be particularly advantageous. Preferably, according to the invention, this is achieved by an embossing roller serving as the embossing tool (P2) and a compound (F1B1) serving as the embossing die (P2) in the form of a coated and at least partially embossed film, preferably a film web, more preferably a continuous film web, which is preferably moving. The composite (F2B2a) to be embossed is moved in the opposite direction by means of a pressure roller. Embossing according to step (2-i) is performed at a nip location formed by counter-rotating rollers arranged at a defined distance from each other. Here, a first roller guiding the composite (F1B1) serving as the embossing die (p2) is used for embossing the composite (F2B2a) guided by a second roller opposing the embossing roller and pressing the composite (F2B2a) to be provided with an embossed structure onto the first embossing roller. As already mentioned above, the structure on the embossing roller, i.e. the structure of the embossing die (p2), may have a continuous structure or may be designed as a discontinuous structure (sequence of individual embossing structures), in which case a combination of both structures is also possible. The corresponding structures on the embossing roll may have any of a wide range of geometries, depending on the intended structure of the composite. If desired, step (2-i) may be carried out at elevated temperature, for example at 30 to 100 ℃ or at least up to 80 ℃. In this case, the compound to be embossed (F2B2a) first passes through a heated roller mechanism and is subsequently irradiated with infrared light, and the actual embossing operation described above is then completed. After embossing, the now embossed composite (F2B2a) is optionally passed through a chill roll mechanism for cooling. Alternatively, step (2-i) may also be carried out with cooling: in this case, the composite to be embossed (F2B2a) is first passed through a chill roll mechanism before the actual embossing operation described above is carried out.

The composition (F1B1) used as embossing die (p2) in step (2-i) is preferably a composite consisting of a film web (F1) and an at least partially embossed and at least partially cured coating (B1) applied thereto.

In carrying out step (2-i), the composite (F1B1) used as the embossing die (P2) in step (2-i) is preferably guided via a first roller used as the embossing tool (P2), and the composite (F2B2a) is guided on a second roller opposite to and counter-rotating or co-rotating with the first roller, preferably counter-rotating.

The at least partial embossing according to step (2-i) is preferably carried out at the level of a nip formed by two counter-rotating or co-rotating opposing rolls with respect to each other, and the at least partially embossed coating (B1) of the composite (B1F1) faces the coating composition (B2a) of the composite (F2B2 a). Here, the at least partial embossing is preferably effected by pressing the composite (F1B1) onto the composite (F2B2 a).

The composite (F1B1) used as embossing die (p2) in step (2-i) consists of a substrate (F1) and an at least partially embossed and at least partially cured coating (B1), hereinafter also referred to as "master substrate" or "master film". In case the substrate (F1) is a film, the corresponding mother film is referred to as "mother foil". In case the substrate (F1) is a foil web, the corresponding mother film is referred to as "mother foil web". The coating layer of the parent film (B1) is hereinafter also referred to as "at least partially cured parent coating layer" or "parent coating film", and the coating composition (B1a) used for preparing the cured parent coating layer is referred to as "parent coating". Between (F1) and (B1) in the complex (F1B1), preferably no further (coating) layer is present. However, at least one adhesion promoter layer may be present between (F1) and (B1) of the compound (F1B1), in which case this layer is preferably transparent to UV radiation.

Optionally, the composite (F1B1) used as embossing die may be pretreated with the coating composition (B2a) used before carrying out step (2-i). The pretreatment comprises or preferably is the wetting of the embossing die with the coating composition (B2 a).

Step (3)

Step (3) of the process of the invention provides for at least partial curing of the coating composition (B2a) in the complex (F2B2aB1F1) obtained after step (2-i) or step (2-ii), so as to obtain a complex (F2B 1F 1); throughout the period of at least partial curing, the coating composition (B2a) was in contact with the part of the assembly (B1F1) of the composite (F2B2aB1F1) that served as the embossing die (p 2).

Steps (2-i) and (3) are preferably carried out simultaneously. In this case, the at least partial curing according to step (3) is preferably carried out in situ during the performance of step (2-i).

Accordingly, the corresponding apparatus for carrying out step (3) preferably comprises at least one radiation source for irradiating the coating composition (B2a) with curing radiation. Since the coating composition (B2a) is preferably a UV-curable coating composition, the curing radiation used is preferably UV radiation. If the coating composition (B2a) is not radiation-curable, it is preferably chemically curable. In this case, the curing in step (3) takes place thermally by using, for example, a suitable thermal radiation source. Of course, a combination of curing, i.e. thermal curing and curing by UV radiation, is also possible.

Examples of suitable radiation sources for radiation curing include low, medium and high pressure mercury emitters as well as fluorescent tubes, pulse emitters, metal halide emitters (halogen lamps), lasers, LEDs, furthermore, electron flash devices capable of radiation curing without photoinitiators, or excimer emitters. Radiation curing occurs by exposure to high-energy radiation, i.e. UV radiation or sunlight, or by bombardment with high-energy electrons. In the case of UV curing, the radiation dose which is generally sufficient for crosslinking is from 80 to 3000mJ/cm². Of course, it is also possible to carry out the curing using two or more radiation sources, for example 2 to 4. These sources may also each emit in a different wavelength range.

The at least partial curing in step (3) is preferably carried out by radiation (F2) through the substrate. In this case, it is advantageous for the transmittance of the substrate (F2) for the radiation used to be coordinated with the permeability of the at least one photoinitiator used, which is preferably present in the coating composition (B2 a). Thus, for example, the material PET (F2) as a substrate, so that the PET film is transparent, for example, to radiation having a wavelength of less than 400 nm. Photoinitiators that generate free radicals from this radiation include, for example, 2,4, 6-trimethylbenzoyldiphenylphosphine oxide, ethyl 2,4, 6-trimethylbenzoylphenylphosphonate, and bis (2,4, 6-trimethylbenzoyl) phenylphosphine oxide. In this case, therefore, it is preferred that at least one such photoinitiator is present in the coating composition (B2 a).

Optional step (4)

Step (4) of the process of the invention provides for optionally removing the composite (F2B2) in the composition (F2B 1F1) from the composite (B1F1) used as embossing die (p 2). Thus, a composite (F2B2) consisting of a substrate (F2) and an at least partially embossed and at least partially cured coating (B2) can be obtained. Preferably, step (4) is performed.

Alternative (ii)

According to alternative (ii), the process of the invention comprises at least steps (1-ii), (2-ii) and (3) and optionally (4). Steps (3) and (4) have been described above in relation to alternative (i).

Step (1-ii)

Step (1-ii) of the process of the present invention provides for applying the coating composition (B2a) onto at least a portion of the at least partially embossed surface of an embossing die (P2) serving as an embossing tool (P2), a composite (B1F1) consisting of a substrate (F1) and an at least partially embossed and at least partially cured coating (B1), thereby obtaining a composite (B2aB1F 1).

Optionally, the composite (F1B1) used as embossing die may be pretreated with the coating composition (B2a) used before carrying out step (1-ii). The pretreatment comprises or preferably is the wetting of the embossing die with the coating composition (B2 a).

Step (2-ii)

Step (2-ii) of the process of the invention provides for applying the substrate (F2) to at least a portion of the surface of the complex (B2aB1F1) formed by (B2a), thus obtaining the complex (F2B2aB1F 1).

Preferably, during the implementation of step (2-ii), after applying the coating composition (B2a) onto at least a portion of the at least partially embossed surface of the composite (B1F1) to obtain the composite (B2aB1F1), the composite (B1F1) used as the embossing die (P2) in step (1-ii) is guided through a first roller used as the embossing tool (P2), and the substrate (F2) used in step (2-ii) is guided through a second roller opposite to and counter-rotating or co-rotating with the first roller, preferably counter-rotating.

The at least partial embossing of step (2-ii) is preferably carried out at the level of a nip formed by two counter-rotating or co-rotating rollers facing each other, with the coating composition (B2a) of the composite (B2aB1F1) facing the substrate (F2). In this case, the at least partial embossing is preferably effected by pressing the substrate (F2) or onto the composite (B2aB1F 1).

FIG. 1 shows schematically a side view of an apparatus which can be used for carrying out steps (1-i) and (2-i) and (3) and optionally (4) of the process according to the invention and serves to illustrate the process according to the invention. The apparatus can likewise be used in a substantially similar manner for carrying out steps (1-ii) and (2-ii) and (3) and optionally (4) of the process of the invention. With the aid of this device, structures such as microstructures and/or nanostructures can be transferred, preferably from an embossing die (F1B1, p2) present as a master film, onto a substrate (F2) coated with (B2 a). Therefore, this device is also commonly referred to as a transfer device, and is given reference numeral (10) in fig. 1.

The core of the transfer device (10) is an embossing zone (1), in which a pressure roller (2) is arranged, which has a roller sleeve made of fused silica. The press roller (2) is driven to rotate. Beside the pressure roller (2) a radiation source in the form of an illumination unit (3) is arranged, which generates UV light and may in particular comprise a row of UV-LEDs arranged in the length direction of the pressure roller (2). As shown in fig. 1, the illumination unit (3) may also be provided inside the pressure roller (2). In the embossing zone (1), a pressure roller (4) is arranged in such a way that it presses against the pressure roller (2). In a die frame (5) of a transfer device (10), two film web rolls (6) and (7) are arranged, which can be driven to rotate by a motor. Of course, the film web rolls (6) and (7) can also be mounted and arranged in a manner different from the die frame (5), for example in a cabinet element or outside the actual transfer device (10). Wound onto web rolls (6) and (7) (shown here as disposed in the die frame) is a parent web (8), which represents a continuous embossing die. On the transfer surface, the master film web (8) is provided with a master coating which is characterized by negative shapes as surface relief of the microstructures and/or nanostructures to be transferred. The master coat is at least partially cured so that the relief structure therein is stable. The mother film web (8) can be obtained by carrying out steps (5) to (8) of the process of the invention, thus constituting the composite (F1B 1). The mother film web (8) is fed away from the first film web roll (6) to the embossing zone (1) via a different deflection roll system and, as shown in fig. 1, enters vertically from above into the region between the pressure roll (2) and the pressure roll (4). In this region, it is guided in tension contact over a portion of the circumference of the pressure roller (2), then leaves the pressure roller (2) again and is supplied to a second film web roll (7) again via a deflection roller system with web tensioners, winding thereon. The film web (9) forming the substrate (F2) provided with structures, such as microstructures and/or nanostructures, starts from a film web roll (11), where it is again supplied via various turning roll systems with web tensioners to the embossing area (1), where it runs taut over a circumferential portion of the pressure roll (4), from where it enters the contact area of the pressure roll (4) on the pressure roll (2), or into the nip area formed between these elements. The film web (9) leaves this zone vertically downwards (in the illustration of fig. 1) and is guided again via a turning roll system and web tensioners to a film web roll (12), on which it is wound into a fully processed product. On its way into the embossing zone (1) or on the nip between the press roll (2) and the press roll (4), the film web (9) is provided with a coating on its surface facing the press roll (2) in the nip (1) by means of a coating application unit (27), in which case the coating application unit is arranged outside the nip (1). Thus, according to step (1-i) of the method of the present invention, the coating application unit (27) applies the coating composition (B2a) to the film web (9) used as (F2). In the nip (1), the film web (9) is then joined by its surface provided with the not yet cured coating to the surface of the parent film web (8) provided with the parent coating in order to carry out step (2-i) of the method of the invention. In this case, the film web (9) is run by means of the pressure roller (4) and the mother film web (8) is run by means of the pressure roller (2). The surfaces of the two webs, i.e. the web (9) and the parent web (8), which are provided with the respective coating layers (in the case of the parent web (8), corresponding to the at least partially cured parent coating layer (B1; in the case of the web (9), corresponding to the uncured coating layer of the coating composition (B2a)) face one another. In the region where the pressure roller (4) is pressed against the pressure roller (2), a negative image of a structure to be transferred such as a microstructure and/or a nanostructure formed in the mother coat (B1) is impressed into the uncured coat corresponding to the coating composition (B2a), thereby transferring the structure. At the same time, the lighting unit (2) performs UV irradiation and thus at least partial curing of the uncured coating (coating composition (B2a) corresponding to the coating on the film web (9)) provided that the coating is still in contact with the master coating (8). Thus, directly during the transfer of the structure and in situ, at least partial curing of the coating is carried out. The irradiation of the film web (9) or of the uncured coating applied thereto is effected here by means of the film material (9) with irradiation from the outside to the press drum (2). Alternatively, the radiation is carried out through the fused silica material of the outer surface of the impression cylinder (2) and also through the material of the mother web (8) and the mother coating applied thereto. The mother web (8) and the mother coating are therefore designed to be transparent to the radiation used, in this case UV light. Here, the outer surface of the press roll (2) is described as being composed of fused silica. However, in principle any other material is also suitable, provided that it is transparent to curing radiation (which may be light other than UV light) emitted from inside the press roll (2). Alternatively, if the coating composition (B2a) is a non-radiation-curable coating composition, it is also possible to use, for example, heat emitters instead of the light-emitting units (3) which provide UV irradiation. One possibility after at least partial curing by UV irradiation is a post-exposure, for example by means of IR radiation. At the end of this curing operation of optional step (4) of the process of the invention, the film web (9) and the parent film web (8) are separated from each other, wherein the now structured layer composite (F2B2) and the parent film (F1B1) are separated. The coated film web (9) thus provided with the desired structure, i.e. the composite (F2B2), is supplied as a finished product to a film web roll (12) and wound up on the roll. The coated film web (9) provided with the desired structure, i.e. the compound (F2B2), can also be opaque if illuminated from the outside onto the pressure roller (2) by means of an illumination unit (3), if the arrangement is chosen such that the main film web (8), i.e. the compound (F1B1), and the film web (9), i.e. the compound (F2B2), are switched. The application by the paint application unit (27) according to step (1-i) of the process of the invention can then be carried out without restricting the operation of the main film web (8). Optional steps (5) to (8) of the process of the invention for preparing a composite (F1B1) for use as an embossing die (p2)

The composite (F1B1) consisting of the substrate (F1) and the at least partially embossed and at least partially cured coating (B1) used in steps (2-i) and (1-ii) of the process is preferably at least obtainable by steps (5) to (8) as explained in more detail below. Thus, steps (5) to (8) of the process of the invention were carried out to prepare the composite (F1B1) for use as an embossing die (p 2). Fig. 2 provides an exemplary illustration of steps (5) to (8) of the method of the invention, as can also be seen from the description of the figure below.

Step (5)

Step (5) of the inventive process provides for applying the radiation curable coating composition (B1a) to at least a portion of the surface of the substrate (F1). The substrate (F1) constitutes the support for the coating composition (B1a) or the coating (B1) applied thereto. The substrate (F1) may be coated. Suitable materials for the base material (F1) or the surface layer thereof include the same materials which can also be used for the preparation of the base material (F2) and which have been mentioned above. And therefore explicit reference is made to the corresponding paragraphs. The substrate (F1) is preferably a film, more preferably a film web, very preferably a continuous film web. A preferred material for the substrate (F1) is polyester, more particularly PET. The thickness of the substrate (F1) is preferably 2 μm to 5 mm. Particularly preferred are layer thicknesses of from 25 to 1000. mu.m, more particularly from 50 to 300. mu.m.

During the implementation of step (5) (and preferably also during the implementation of steps (6), (7) and (8) of the process), the substrate (F1) is preferably moving, and therefore a moving substrate. During the execution of step (5), the substrate is preferably moved by means of a conveying device, such as a conveyor belt (F1). Accordingly, the corresponding apparatus for carrying out step (5) preferably comprises such a conveying apparatus. The corresponding apparatus for carrying out step (5) further comprises means for applying the preferably radiation-curable coating composition (B1a) onto at least a part of the surface of the substrate (F1).

Step (6)

Step (6) of the process of the invention provides for at least partially embossing the coating composition (B1a) applied at least partially to the surface of the substrate (F1) by means of at least one embossing tool (P1) having at least one embossing die (P1). The at least partial embossing at least partially transfers the embossed structure to a surface of a coating composition (B1a) applied to a substrate (F1). The term "embossing" has been defined above. Thus, as far as (B1a) or (B1) is concerned, it relates to at least partially finishing with an embossed structure a coating composition (B1a) as part of a composite (F1B1 a). In this case, at least certain regions of the coating composition (B1a) are decorated with an embossed structure. Preferably, as part of the composite (F1B1a), the entire surface of the coating composition (B1a) is decorated with an embossed structure. During the implementation of step (6), the embossing tool (P1) is preferably pressed or at least partially pressed onto the applied coating composition (B1 a).

Step (6) preferably transfers the microstructures and/or nanostructures as embossed structures onto the coating composition (B1 a).

Accordingly, the respective apparatus for carrying out step (6) comprises an apparatus for at least partially embossing a coating composition (B1a) by means of at least one embossing tool (P1), said coating composition being at least partially applied onto the surface of the substrate (F1). The apparatus used preferably further comprises, after application of the radiation-curable coating composition (B1a) to (F1), a device for pressing (P1) onto the substrate (F1), preferably used in the form of a continuous film web, which is preferably located downstream of the device for applying the radiation-curable coating composition (B1a), viewed in the transport direction of the substrate (F1).

At least partial embossing according to step (6) of the method according to the invention is carried out by means of an embossing tool (P1). (P1) may preferably be an embossing calender, which preferably comprises a grid application mechanism, more preferably a grid roller mechanism. The calender has counter-rotating rolls, preferably arranged one above the other at intervals in the height direction, and the compound (F1B1a) to be provided with an embossed structure is supplied to the rolls and guided through the nip formed, wherein the nip width is variably adjustable. Here, the grid roller mechanism preferably comprises a first roller, for example a metal roller, for example a steel roller or a nickel roller, and a second roller. Here, the first roller (embossing roller) serves as an embossing tool (P1), and contains a negative type of an embossing structure, which is to be embossed into the surface of the complex (F1B1 a). This corresponds to the positive structure to be embossed into the composite (F2B2a) in step (2) of the method. The second roll is used as an embossing roll or a pressure roll. -generating a positive version of the structure to be embossed on an embossing tool (P1) according to methods conventional and known to the person skilled in the art; depending on the structure and materials, particular methods may be particularly advantageous. According to the invention, this is preferably achieved by means of an embossing roller serving as embossing tool (P1) and comprising an embossing die (P1). The compound to be embossed (F1B1a) in the form of a film web, for example at least partially coated with (B1a), is moved in the opposite direction by means of a press roll. Embossing according to step (6) is performed at the nip location formed by counter-rotating rollers arranged at a distance from each other. Here, a first roller with an embossing die (p1) is used for embossing the composite (F1B1a) guided by a second roller opposite the embossing roller, wherein the second roller presses the composite (F1B1a) to be provided with an embossed structure against the first embossing roller. If desired, step (6) may be carried out at elevated temperature, for example at 30-100 ℃ or up to 80 ℃. In this case, the composite (F1B1a) used for embossing is first passed through a heated roller mechanism, optionally followed by irradiation with infrared light, and then subjected to the actual embossing procedure described above. After embossing, the now embossed composite (F1B1a) is optionally passed through a chill roll mechanism to cool. Alternatively, step (6) may be carried out under cooling: in this case, the composite (F1B1a) used for embossing is first passed through a chill roll mechanism, and then the actual embossing process described above is performed. The embossing tool (P1) used may also be a conventional press cylinder carrying the negative of the embossing structure to be embossed into the surface of the composite (F1B1 a). The cartridge may be pressed onto the compound (F1B1a) to at least partially emboss.

The at least one embossing die (P1) used for the embossing tool (P1) at least partially embossed according to step (6) has a "positive structure" ("positive"), i.e. it has an embossed structure shown by the coating (F2B2) obtained after carrying out step (4) of the process of the invention and consisting of the substrate (F2) and the at least partially embossed and fully cured coating (B2). The embossing tool (P1) is preferably a metal embossing tool, more preferably made of nickel. Thus, the embossing die (p1) is preferably metallic, more preferably made of nickel, more particularly nickel containing a small amount of phosphorus. Alternatively, however, a soft material such as Polydimethylsiloxane (PDMS) may also be used to produce (p 1). Furthermore, rolls coated with at least one plastic may be used. Furthermore, the embossing tool (P1) may have a structured coating such as a UV coating as the embossing die. After step (6) is carried out, the coating composition (B1a) applied on (F1) exhibits a negative of the embossed structure to be transferred, such as a micro-structure and/or a nano-structure.

The embossing die of the embossing tool used may optionally be pretreated with the coating composition (B1a) used before carrying out step (6). The pretreatment comprises or preferably is the wetting of the embossing die with the coating composition (B1 a).

Step (7)

Step (7) of the process of the invention provides for at least partial curing, preferably complete curing, of the at least partially embossed coating composition (B1a) applied to at least a portion of the surface of the substrate (F1), so as to obtain a composite (F1B1) consisting of the substrate (F1) and the at least partially embossed and at least partially cured coating (P1); throughout at least curing, the coating composition (B1a) is contacted with at least one embossing die (P1) of at least one embossing tool (P1).

Steps (6) and (7) are preferably carried out simultaneously. In this case, the curing of step (7) is preferably carried out in situ during the execution of step (6).

Accordingly, the respective apparatus for carrying out step (7) preferably comprises at least one radiation source for irradiating the radiation-curable coating composition (B1a) with curing radiation, preferably UV radiation.

Examples of suitable radiation sources for radiation curing include low, medium and high pressure mercury emitters as well as fluorescent tubes, pulse emitters, metal halide emitters (halogen lamps), lasers, LEDs, furthermore, electron flash devices capable of radiation curing without photoinitiators, or excimer emitters. Radiation curing occurs by exposure to high-energy radiation, i.e. UV radiation or sunlight, or by bombardment with high-energy electrons. In the case of UV curing, the radiation dose which is generally sufficient for crosslinking is from 80 to 3000mJ/cm². Of course, curing can also be carried out using two or more radiation sources, for example 2 to 4. These sources may also each emit in a different wavelength range.

The curing in step (7) is preferably carried out by radiation (F1) through the substrate. In this case, it is advantageous for the transmittance of the substrate (F1) for the radiation used to be coordinated with the at least one photoinitiator used as component (c). Thus, for example, the material PET (F1) as substrate, and therefore PET film, is transparent to radiation having a wavelength of less than 400 nm. Photoinitiators that generate free radicals from this radiation include, for example, 2,4, 6-trimethylbenzoyldiphenylphosphine oxide, ethyl 2,4, 6-trimethylbenzoylphenylphosphonate, and bis (2,4, 6-trimethylbenzoyl) phenylphosphine oxide.

Step (8)

Step (8) of the process of the invention provides for the removal of the composite (F1B1) from the embossing tool (P1), thereby producing the desired product, namely a composite (F1B1) consisting of a substrate (F1) and an at least partially embossed and at least partially cured coating (B1) serving as an embossing die (P2).

Fig. 2 schematically shows a side view of an apparatus which can be used for carrying out steps (5) to (8) of the method of the invention for preparing a composite (F1B1) (used as (p2)), i.e. for preparing a master film, and which serves to exemplarily show the method of the invention in connection with steps (5) to (8). With this apparatus, structures such as microstructures and/or nanostructures can be transferred onto a substrate (F1) coated with (B1a) with the aid of an embossing tool (P1), and after at least partial curing, a composite (F1B1) is produced that can be used as a master film, referred to as master film web (8) in fig. 2, which can be used as an embossing die (P2), as described above in connection with the method shown in fig. 1.

The master film transfer device (30) shown in fig. 2 operates according to the transfer principle, wherein the desired negative-type structure is embossed directly from a structured press cylinder or roller, here the master film cylinder (17), into the not yet cured coating applied to the master film web (8B) corresponding to the compound (F1B1a), which is then at least partially cured together with the structure applied thereto, wherein the curing is carried out in situ by means of an illumination unit (3) to obtain the master film web (8) corresponding to the compound (F1B 1). In the method, a film web (8a) serving as a substrate (F1) is drawn from a film web roll (18) containing only the carrier material, in other words, the pure film without the application of a master coat, and is guided through various turning roll systems and web tensioning systems and introduced into the embossing area (1) of the apparatus. There, the film web (8a) runs into the region between the press roll (4) and the master press cylinder (17) and outside the press region, in a coating application device (27), a not yet cured master coating (corresponding to coating composition B1a) is provided. The application of such a coating corresponds to step (5) of the method of the invention. In an embossing region (1) in which a mother film web (8b) having a not yet cured mother coating runs along a part of the outer surface of a mother impression cylinder (17), microstructures and/or nanostructures embossed into the outer surface of the mother impression cylinder (17) are introduced as a negative image into the mother coating of the mother film web (8b) and transferred. This corresponds to step (6) of the method of the invention. The mother web (8B) comprising the uncured coating composition (B1a) is then at least partially cured according to step (7) of the process of the present invention. Here, the curing is carried out in situ by irradiation with an illumination unit (3), by means of UV radiation, for example by means of a unit consisting of UV-LEDs. Subsequently, according to step (8) of the process of the invention, the resulting mother film (8), in other words the composite (F1B1), is removed from the outer surface of the mother-pressing cylinder (17) and the thus completed mother film web (8) is wound onto a film web roll (19). The film web roll (19) then comprises a finished master film web (8) having a master coating applied thereto and having a negative image of the microstructures and/or nanostructures embossed therein. This film web roll (19) can be removed and then used as the first film web roll (6) in a transfer device (10) according to fig. 1 or in another transfer device operating on the same principle.

Coating compositions (B1a) and (B2a) used in the present invention

Coating composition (B1a)

The coating composition (B1a) is a radiation-curable coating composition. Herein, the terms "radiation curable" and "radiation curing" are interchangeable. The term "radiation curing" preferably means free-radical polymerization of polymerizable compounds by means of electromagnetic and/or particle radiation, examples being (N) at λ ═>(N) IR light in the wavelength range 400-²Preferably 80 to 3000mJ/cm². Particularly preferably, the radiation curing used is UV radiation. The coating composition (B1a) can be cured by using a suitable radiation source. Therefore, (B1a) is preferably a UV radiation-curable coating composition.

The coating composition (B1a) comprises:

from 40 to 95% by weight, preferably from 45 or > 45% by weight to 90% by weight, more preferably from 50 or > 50% by weight, for example from 55 to 85% by weight, very preferably from 55 or 60 to 80% by weight, of the at least one component (a),

as component (b) in an amount of from 0.01 to 5% by weight, preferably from 0.05 to 4.5% by weight, more preferably from 0.1 to 4% by weight, very preferably from 0.2 or from 0.5 to 3% by weight,

as component (c) at least one photoinitiator in an amount of from 0.01 to 15% by weight, preferably from 0.1 to 12% by weight, more preferably from 0.5 to 10% by weight,

in an amount of from 0 to 45% by weight, preferably from 0 to 40% by weight, more preferably from 0 to 35% by weight, very preferably from 0 to 30% by weight, of at least one component (d) having at least one carbon double bond,

in each case based on the total weight of the coating composition (B1 a).

Thus, the presence of component (d) in the coating composition (B1a) used according to the invention is only optional, as can be seen from the lower limit of 0% by weight indicated above. Preferably, the coating composition (B1a) comprises component (d) in an amount of up to 30 wt. -%, based on the total weight of the coating composition (B1 a).

The components (a), (b), (c) and (d) are each different from one another. The stated amounts of components (a), (B), (c) and (d) are in each case based on the total weight of the coating composition (B1 a). The amounts of all components present in the coating composition (B1a), i.e. the amounts of components (a), (B) and (c) and optionally (d) and optionally further components present in (B1a) add up to 100% by weight.

Component (a) has at least 3 structural units of the formula (I), in each case different from one another or at least partially identical:

wherein:

radical R¹Each independently of the other is C₂-C₈An alkylene group or a substituted alkylene group,

radical R²Each independently of the other is H or methyl, and

the parameters m are each, independently of one another, an integer parameter from 1 to 15, preferably from 1 to 10, more preferably from 1 to 8 or from 2 to 8, very preferably from 1 to 6 or from 2 to 6, more particularly from 1 to 4 or from 2 to 4, with the proviso that in at least one structural unit of the formula (I), the parameter m is at least 2, preferably at least 3.

Component (a) preferably has at least 3 identical structural units of the formula (I).

Here, the symbolsDenotes the bond of the respective radical to the upper structure of component (a), in other words, for example, denotes the radical- [ O-R ] in the structural unit of the formula (I)¹]_m-O-C(＝O)-C(R²)＝CH₂A bond to the upper structure of component (a). The bonding is preferably via the group- [ O-R ]¹]_m-oxygen atom is bonded to a carbon atom of the upper group. Similar remarks apply to the other structural units of formula (I). It is clear that all at least 3 structural units of the formula (I) are combined in a single component, in particular in component (a).

Component (a) preferably has exactly 3 structural units of the formula (I). In this case, component (a) has exactly 3 functional (meth) acrylic groups. Alternatively, the structural units of the formula (I) may also each be present more than 3 times as part of component (a). In this case, for example, component (a) may have more than 3 (meth) acrylic functional groups, for example 4, 5 or 6 (meth) acrylic groups.

The above-mentioned radical R¹Each independently of the other is C₂-C₈Alkylene, preferably C₂-C₆Alkylene, more preferably C₂-C₄Alkylene, very preferably each independently of the other, is ethylene and/or propylene, particularly preferably ethylene. In particular, all radicals R¹Is an ethylene group. In each case, suitable as propylene radicals are those having the structure-CH₂-CH₂-CH₂Or the structure-CH (CH)₃)-CH₂Or the structure-CH₂-CH(CH₃) Group R of (A)¹. However, particular preference is given in each case to the propylene structure-CH₂-CH₂-CH₂-。

The parameter m is in each case, independently of one another, an integer from 1 to 15, since the component (a) has at least 3 structural units of the formula (I) and since in at least one structural unit of the formula (I) the parameter m is at least2, component (a) thus comprises a total of at least 4 of the formulae "-O-R¹- "an ether group.

Preferably, component (a) has at least 5, more preferably at least 6, total of the formula "-O-R¹- "an ether group. The general formula-O-R in component (a)¹The number of ether groups of the- "is preferably from 4 to 18, more preferably from 5 to 15, very preferably from 6 to 12.

An ether segment- [ O-R ] present in the structural unit of the formula (I) of component (a)¹]_mIn total, is at least 35 wt.%, more preferably at least 38 wt.%, very preferably at least 40 wt.%, still more preferably at least 42 wt.%, more particularly at least 45 wt.%, in each case based on the total weight of component (a).

The molecular weight (Mn) of component (a) is preferably 300-2000g/mol, more preferably 350-1500g/mol, more particularly 400-1000 g/mol.

Particularly preferred for use as component (a) is at least one compound of the general formulae (IVa) and/or (IVb):

wherein in each case independently of one another,

R¹and R²And m has the meaning given above for structural unit (I), including the preferred embodiments described above, and

R³is H, C₁-C₈Alkyl, OH or O-C_1-8Alkyl, more preferably C₁-C₄Alkyl, OH or O-C_1-4Alkyl, very preferably C₁-C₄Alkyl or OH, or

R3 is a group- [ O-R ]¹]_m-O-C(＝O)-C(R²)＝CH₂Wherein R is¹、R²And m has the definitions described above for structural unit (I), including preferred embodiments thereof described above.

Particular preference is given to using at least one compound of the general formula (IVa) as component (a), in which:

radical R¹Each being independent of each otherThe standing is C₂-C₈An alkylene group or a substituted alkylene group,

radical R²Each independently of the other being H or methyl,

the parameter m is in each case, independently of one another, an integer parameter from 1 to 15, preferably from 1 to 10, more preferably from 1 to 8 or from 2 to 8, very preferably from 1 to 6 or from 2 to 6, more particularly from 1 to 4 or from 2 to 4, with the proviso that in at least one, preferably in all, structural units of the formula (I), the parameter m is at least 2,

R³is C₁-C₈Alkyl, OH or O-C_1-8Alkyl, more preferably C₁-C₄Alkyl, OH or O-C_1-4Alkyl, very preferably C₁-C₄Alkyl or OH.

Particularly preferred for use as component (a) are (meth) acrylates of neopentyl glycol, trimethylolpropane, trimethylolethane or pentaerythritol, wherein neopentyl glycol, trimethylolpropane, trimethylolethane or pentaerythritol is alkoxylated in total 4 to 20 times, or 4 to 12 times, for example ethoxylated, propoxylated or mixed ethoxylated and propoxylated, more particularly only ethoxylated. Most preferred are the corresponding (meth) acrylates derived from the corresponding alkoxylated trimethylolpropane. These kinds of products are commercially available and are for example known by nameSR 499 andSR502 and

SR 415 and

SR 9035 andSR 501. In the sense of the present invention, the term "(meth) acrylic" or "(meth) acrylate" encompasses not only methacrylic acidClass, but also acrylic, and encompass not only methacrylates, but also acrylates.

In addition to optional component (d), the coating composition (B1a) preferably contains no components having only exactly one or only exactly two ethylenically unsaturated groups, such as (meth) acrylic groups. Thus, when (B1a) has no component (d), (B1a) preferably contains no component having only exactly one or only exactly two ethylenically unsaturated groups, such as (meth) acrylic groups.

Component (b) is an additive. The concept of additives is known to the person skilled in the art, for example fromLexikon, "Lacke und Druckfarben", Thieme Verlag, 1998, page 13 is known. The preferred component (b) used is at least one rheological additive. The term is also known to the person skilled in the art, for example byLexikon, "Lacke und Druckfarben", Thieme Verlag, 1998, page 497. Herein, the terms "rheological additive", "rheology additive" and "rheology aid" are interchangeable. The additives used as component (b) are preferably selected from flow regulators, surface-active agents such as surfactants, wetting agents and dispersants, and also thickeners, thixotropic agents, plasticizers, lubricating and antiblocking additives, and mixtures thereof. These terms are likewise known to the person skilled in the art, for example from

Lexikon, "Lacke und Druckfarben", Thieme Verlag, 1998. Flow control agents are components that help the coating to form a uniform flowing film by reducing viscosity and/or surface tension. Wetting agents and dispersants are components that lower surface tension or generally lower interfacial tension. Lubricity and antiblock additives are components that reduce mutual sticking (blocking).

Examples of commercially available additives are products

SL 3259、377、Rad 2500、Rad 2800、394、Byk-SILCLEAN 3710、

A250, Novec FC 4430 and Novec FC 4432.

Preferably used as additive (B) are at least one poly (meth) acrylate and/or at least one siloxane, such as at least one oligosiloxane and/or polysiloxane and/or at least one fluoropolymer, such as a fluorine-containing, preferably aliphatic, polyester. Particularly preferred components (b) are siloxanes. Particularly preferably used are silicone (meth) acrylates.

For curing by means of (N) IR and/or UV light, the coating composition (B1a) comprises at least one photoinitiator as component (c). The photoinitiator is decomposable into free radicals by light of an irradiation wavelength, which in turn can initiate free radical polymerization. In contrast, in the case of curing with electron radiation, the presence of such a photoinitiator is not required. The coating composition (B1a) preferably comprises, as component (c), at least one photoinitiator which is decomposable by light of an irradiation wavelength into free radicals which in turn are capable of initiating free radical polymerization.

Photoinitiators, such as UV photoinitiators, are known to the person skilled in the art. Examples of those envisaged include phosphine oxides, benzophenones, alpha-hydroxyalkylarylketones, thioxanthones, anthraquinones, acetophenone ketones, benzoins and benzoin ethers, ketals, imidazoles or phenylglyoxylic acids and mixtures thereof.

Phosphine oxides are, for example, monoacyl-or bisacylphosphine oxides, such as 2,4, 6-trimethylbenzoyldiphenylphosphine oxide, ethyl 2,4, 6-trimethylbenzoylphenylphosphinate or bis- (2, 6-dimethoxybenzoyl) -2,4, 4-trimethylpentylphosphine oxide. Benzophenones, for example, benzophenone, 4-aminobenzophenone, 4' -bis (dimethylamino) benzophenone, 4-phenylbenzophenone, 4-chlorobenzophenone, Michler's ketone, o-methoxybenzophenone, 2,4, 6-trimethylbenzophenone, 4-methylbenzophenone, 2, 4-dimethylbenzophenone, 4-isopropyl benzophenone, 2-chlorobenzophenone, 2' -dichlorobenzophenone, 4-methoxybenzophenone, 4-propoxy benzophenone or 4-butoxy benzophenone; alpha-hydroxyalkylarylketones are, for example, 1-benzoylcyclohex-1-ol (1-hydroxycyclohexylphenylketone), 2-hydroxy-2, 2-dimethylacetophenone (2-hydroxy-2-methyl-1-phenylpropan-1-one), 1-hydroxyacetophenone, 1- [4- (2-hydroxyethoxy) phenyl ] -2-hydroxy-2-methyl-1-propan-1-one or polymers containing 2-hydroxy-2-methyl-1- (4-isopropen-2-ylphenyl) -propan-1-one in copolymerized form. Xanthones and thioxanthones are, for example, 10-thioxanthone, thioxanth-9-one, xanthen-9-one, 2, 4-dimethylthioxanthone, 2, 4-diethylthioxanthone, 2, 4-diisopropylthioxanthone, 2, 4-dichlorothioxanthone or chloroxanthone; the anthraquinones include, for example, β -methylanthraquinone, tert-butylanthraquinone, anthraquinone carboxylate, benzo [ de ] anthracen-7-one, benzo [ a ] -anthracen-7, 12-dione, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone or 2-amylanthraquinone. Acetophenone, acetyl naphthoquinone, pentanone, hexanone, alpha-phenylbenzone, p-morpholinopropiophenone, dibenzosuberone, 4-morpholinobenzophenone, p-diacetylbenzene, 4' -methoxyacetophenone, alpha-tetralone, 9-acetylphenanthrene, 2-acetylphenanthrene, 3-acetylindole, 9-fluorenone, 1-indanone, 1,3, 4-triacetylbenzene, 1-naphthalenone, 2-dimethoxy-2-phenylacetophenone, 2-diethoxy-2-phenylacetophenone, 1-dichloroacetophenone, 1-hydroxyacetophenone, 2-diethoxyacetophenone, 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinoacetophenone Propan-1-one, 2-dimethoxy-1, 2-diphenylethan-2-one or 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one. Benzoins and benzoin ethers are for example 4-morpholinodeoxybenzoin, benzoin isobutyl ether, benzoin tetrahydropyranyl ether, benzoin methyl ether, benzoin ethyl ether, benzoin butyl ether, benzoin isopropyl ether or 7H-benzoin methyl ether. Ketals are, for example, acetophenone dimethyl ketal, 2-diethoxyacetophenone or benzil ketals, for example benzil dimethyl ketal. Photoinitiators which can also be used are, for example, benzaldehyde, methyl ethyl ketone, 1-naphthaldehyde, triphenylphosphine, tri-o-tolylphosphine or 2, 3-butanedione. Typical mixtures include, for example, 2-hydroxy-2-methyl-1-phenylpropan-2-one and 1-hydroxycyclohexylphenyl ketone, bis (2, 6-dimethoxybenzoyl) -2,4, 4-trimethylpentylphosphine oxide and 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzophenone and 1-hydroxycyclohexylphenyl ketone, bis (2, 6-dimethoxybenzoyl) -2,4, 4-trimethylpentylphosphine oxide and 1-hydroxycyclohexylphenyl ketone, 2,4, 6-trimethylbenzoyldiphenylphosphine oxide and 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,4, 6-trimethylbenzophenone and 4-methylbenzophenone, or 2,4, 6-trimethylbenzophenone and 4-methylbenzophenone and 2,4, 6-trimethylbenzoyldiphenylphosphine oxide.

Preferred among these photoinitiators are 2,4, 6-trimethylbenzoyldiphenylphosphine oxide, ethyl 2,4, 6-trimethylbenzoylphenylphosphonate, bis (2,4, 6-trimethylbenzoyl) phenylphosphine oxide, benzophenone, 1-benzoylcyclohex-1-ol, 2-hydroxy-2, 2-dimethylacetophenone and 2, 2-dimethoxy-2-phenylacetophenone. Therefore, it is preferred to use at least one such photoinitiator as component (c). Component (c) is different from components (a), (b) and (d). Commercially available photoinitiators are, for example, the products

184、

500、TPO、TPO-L and

TPO and

1173, obtained from BASF SE.

As mentioned above, the use of at least one component (d) is only optional. Component (d) has at least one, preferably terminal, carbon double bond. This is preferably a (meth) acrylic group. Component (d) preferably has 1 or 2 ethylenically unsaturated groups, for example 1 or 2 or 3 or more (meth) acrylic groups. Two or more different components (d) may also be used.

Examples of component (d) are mono-, di-and/or tri-functional (meth) acrylates, such as ethylene glycol di (meth) acrylate, 1, 2-propanediol di (meth) acrylate, 1, 3-propanediol di (meth) acrylate, 1, 4-butanediol di (meth) acrylate, 1, 3-butanediol di (meth) acrylate, 1, 5-pentanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 8-octanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,1-, 1,2-, 1, 3-and 1, 4-cyclohexanedimethanol di (meth) acrylate, 1,2-, 1, 3-or 1, 4-cyclohexanediol di (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane penta-or hexa (meth) acrylate, pentaerythritol tri-or tetra (meth) acrylate, glyceryl di-or tri (meth) acrylate, and di-and poly (meth) acrylates of sugar alcohols such as sorbitol, mannitol, diglycerol, threitol, erythritol, adonitol (ribitol), arabitol (lyxitol), xylitol, dulcitol (galactitol), maltitol or isomalt, 2-phenoxyethyl (meth) acrylate, ethyl diglycol (meth) acrylate, 4-tert-butylcyclohexyl (meth) acrylate, trimethylolpropane formal mono (meth) acrylate, isobornyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2- (2-ethoxyethoxy) ethyl (meth) acrylate and lauryl, stearyl, isodecyl, octyl and decyl (meth) acrylate, esters of α, β -ethylenically unsaturated carboxylic acids, preferably (meth) acrylic acid, with alcohols having 1 to 20 carbon atoms, preferably hydroxy-substituted alkanols optionally having 1 to 20 carbon atoms, for example methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate or 4-hydroxybutyl (meth) acrylate.

Particularly preferred components (d) are 1, 4-butanediol di (meth) acrylate and 1, 6-hexanediol di (meth) acrylate and tricyclodecane dimethanol di (meth) acrylate.

As component (d), additionally or alternatively, at least one polyester, polyether, carbonate, epoxide, poly (meth) acrylate and/or polyurethane (meth) acrylate and/or unsaturated polyester resin can also be used.

Polyurethane (meth) acrylates can be obtained, for example, by reacting polyisocyanates with hydroxyalkyl (meth) acrylates and optionally chain extenders such as diols, polyols, diamines, polyamines or dithiols or polythiols. Polyurethane (meth) acrylates which can be dispersed in water without the addition of emulsifiers additionally contain ionic and/or nonionic hydrophilic groups which are incorporated into the urethane by synthetic components such as hydroxycarboxylic acids. The polyurethane (meth) acrylate essentially comprises as synthesis components:

(a) at least one organic aliphatic, aromatic or cycloaliphatic di-or polyisocyanate, for example at least one polyisocyanate as described above for the two-component coating,

(b) at least one compound having at least one isocyanate-reactive group (preferably one of the hydroxyl-bearing monomers described above for the polyacrylate polyol) and at least one free-radically polymerizable unsaturated group, and

(c) optionally, at least one compound having at least two isocyanate-reactive groups, such as one of the polyols described above for the polyesterol.

The number-average molecular weight Mn of the polyurethane (meth) acrylates is preferably 200-20000g/mol, more particularly 500-10000g/mol, very preferably 600-3000g/mol (determined by gel permeation chromatography using tetrahydrofuran and polystyrene standards). The urethane (meth) acrylate preferably contains 1 to 5mol, more preferably 2 to 4mol of (meth) acrylic group per 1000g of urethane (meth) acrylate.

Epoxidized (meth) acrylates can be obtained by reacting epoxides with (meth) acrylic acid. Examples of epoxides envisaged include epoxidized olefins, aromatic glycidyl ethers or aliphatic glycidyl ethers, preferably those of aromatic or aliphatic glycidyl ethers. Examples of possible epoxidized olefins include ethylene oxide, propylene oxide, isobutylene oxide, 1-butylene oxide, 2-butylene oxide, vinyl ethylene oxide, styrene oxide or epichlorohydrin; preference is given to ethylene oxide, propylene oxide, isobutylene oxide, vinyloxirane, styrene oxide or epichlorohydrin, particular preference to ethylene oxide, propylene oxide or epichlorohydrin, particular preference to ethylene oxide and epichlorohydrin. Aromatic glycidyl ethers are, for example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol B diglycidyl ether, bisphenol S diglycidyl ether, hydroquinone diglycidyl ether, the alkylation products of phenol/dicyclopentadiene, such as 2, 5-bis [ (2, 3-epoxypropoxy) phenyl ] octahydro-4, 7-methylene-5H-indene, tris [4- (2, 3-epoxypropoxy) phenyl ] methane isomer, phenol-based epoxy novolaks and cresol-based epoxy novolaks. Aliphatic glycidyl ethers are, for example, 1, 4-butanediol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, 1,2, 2-tetrakis [4- (2, 3-epoxypropoxy) phenyl ] ethane, the diglycidyl ether of polypropylene glycol (. alpha.,. omega. -bis (2, 3-epoxypropoxy) polyoxypropylene and the diglycidyl ether of hydrogenated bisphenol A (2, 2-bis [4- (2, 3-epoxypropoxy) cyclohexyl ] propane). the epoxidized (meth) acrylate preferably has a number-average molecular weight Mn of 200-, more preferably 2-4mol (as determined by gel permeation chromatography using polystyrene as standard and tetrahydrofuran as eluent).

The (meth) acrylated poly (meth) acrylates are the corresponding esters of α, β -ethylenically unsaturated carboxylic acids, preferably (meth) acrylic acid, more preferably acrylic acid, and polyacrylate polyols, which are obtainable by esterifying poly (meth) acrylate polyols with (meth) acrylic acid. The polyacrylate polyols can be, for example, those described above for two-component coatings.

The carbonate (meth) acrylate may have various functional groups. The number-average molecular weight Mn of the carbonate (meth) acrylates is preferably less than 3000g/mol, more preferably less than 1500g/mol, very preferably less than 800g/mol (determined by gel permeation chromatography using polystyrene as standard and tetrahydrofuran solvent). Carbonate (meth) acrylates can be obtained in a simple manner by transesterification of carbonates with polyhydric alcohols, preferably dihydric alcohols (diols, for example hexanediol) and subsequent esterification of the free OH groups with (meth) acrylic acid or transesterification with (meth) acrylates, as described, for example, in EP0092269A 1. They can also be obtained by reaction of phosgene, urea derivatives and polyols, for example diols. Also conceivable are (meth) acrylates of polycarbonate polyols, for example the reaction products of one of the diols or polyols with carbonates and also hydroxyl-containing (meth) acrylates. Examples of suitable carbonates are ethylene carbonate, 1, 2-or 1, 3-propylene carbonate, dimethyl carbonate, diethyl carbonate or dibutyl carbonate. Examples of suitable hydroxyl-containing (meth) acrylates are 2-hydroxyethyl (meth) acrylate, 2-or 3-hydroxypropyl (meth) acrylate, 1, 4-butanediol mono (meth) acrylate, neopentyl glycol mono (meth) acrylate, glyceryl mono-and di (meth) acrylates, trimethylolpropane mono-and di (meth) acrylates and pentaerythritol mono-, di-and tri (meth) acrylates. Preferably, the carbonate (meth) acrylate is an aliphatic carbonate (meth) acrylate.

The unsaturated polyester resin is preferably composed of the following components:

(a1) the maleic acid or a derivative thereof, or a salt thereof,

(a2) at least one cyclic dicarboxylic acid or a derivative thereof,

(a3) at least one aliphatic or cycloaliphatic diol.

Here, the derivatives preferably mean:

-the related anhydride in monomeric or polymeric form,

mono-or dialkyl esters, preferably mono-or di-C₁-C₄Alkyl esters, more preferably monomethyl or dimethyl esters or the corresponding monoethyl or diethyl esters,

furthermore, monovinyl and divinyl esters, and

mixed esters, preferably with different C₁-C₄Mixed esters of alkyl components, more preferably mixed methylethyl esters.

If (B1a) comprises component (d), this component is preferably at least one polyurethane (meth) acrylate.

The coating composition (B1a) may comprise at least one further component (e) different from components (a) to (d), for example fillers, pigments, heat-activatable initiators such as potassium peroxodisulfate, dibenzoyl peroxide, cyclohexanone peroxide, azobisisobutyronitrile, cyclohexylsulfonyl acetyl peroxide, diisopropyl percarbonate, tert-butyl peroctoate or benzopinacol, di-tert-butyl peroxide, cumene hydroperoxide, dicumyl peroxide, tert-butyl perbenzoate, silylated pinacol, amine N-oxides containing hydroxyl groups such as 2,2,6, 6-tetramethylpiperidine-N-oxyl and 4-hydroxy-2, 2,6, 6-tetramethylpiperidine-N-oxyl, and organic solvents and stabilizers. However, it is preferable that the organic solvent is not included in (B1 a). Component (e) may be present in (B1a) in an amount of from 0 to 15% by weight, preferably from 0 to 12% by weight, more preferably from 0 to 10% by weight, in each case based on the total weight of the coating composition (B1 a).

The solids content of the coating composition (B1a) is preferably 80% by weight or more, more preferably 90% by weight or more, very preferably 95% by weight or more, more particularly 98% by weight or 99% by weight or more, most preferably 100% by weight, based in each case on the total weight of the coating composition (B1 a). Here, the solid content was measured by the following method.

The coating composition (B1a) is preferably free of mercaptans, in particular free of trimethylolpropane tris (3-mercaptopropionate).

The conversion of double bonds of the at least partially cured coating (B1) obtained from (B1a) is preferably at least 70%, more preferably at least 75%, still more preferably at least 80%, very preferably at least 85%, more particularly at least 90%.

Coating composition (B2a)

Any kind of coating composition may be used as the coating composition (B2a) in step (1) of the process of the present invention. The coating composition (B2a) may be a physically drying, thermally curable, chemically curable and/or radiation curable coating composition (B2 a). Preferably, the coating composition (B2a) is a chemically curable, thermally curable and/or radiation curable coating composition, more preferably a radiation curable coating composition. Thus, the at least partial curing of step (3) is preferably carried out by radiation curing. The coating composition (B2a) may be the same as the coating composition (B1 a). However, it is preferable that (B2a) is different from (B1 a). (B2a) is preferably composed of identical but different components (a) to (e) which are also used for the preparation of (B1a), although the quantitative restrictions with respect to (B1a) do not necessarily apply to (B2 a).

Here, physical drying preferably means simply evaporating the solvent to form a coating layer (B2). Here, thermal curing preferably requires a curing mechanism attributable to a temperature (>23 ℃) higher than room temperature. This may for example be the formation of free radicals or ions, preferably free radicals from initiators which decompose at elevated temperatures and thus initiate free radical or ionic polymerization. Examples of such heat-activatable initiators are those having a half-life of less than 100 hours at 80 ℃. Chemical curing preferably means a reaction of at least two different and mutually complementary reactive functional groups, for example a polycondensation reaction, for example a reaction of-OH groups with-COOH groups, or an polyaddition reaction (reaction of NCO groups with-OH or amino groups).

If the coating composition (B2a) is a physically drying, thermally and/or chemically curable coating composition, it is prepared using at least one conventional polymer known to the person skilled in the art as binder. In this case, the binder preferably has a crosslinkable functional group. Any conventional crosslinkable functional group known to those skilled in the art is suitable for use in the present invention. More particularly, the crosslinkable functional group is selected from the group consisting of a hydroxyl group, an amino group, a carboxylic acid group, an isocyanate group, a polyisocyanate group and an epoxy group. The polymers are preferably curable or crosslinkable exothermically or endothermically, preferably in the temperature range from-20 ℃ to 250 ℃ or 18-200 ℃. Particularly suitable as polymers are at least one polymer selected from the group consisting of polyurethanes, polyethers, polyesters, polyamides, polyureas, polyvinyl chlorides, polystyrenes, polycarbonates, poly (meth) acrylates, epoxy resins, phenolic resins, melamine-formaldehyde resins. In particular, these polymers may be OH-functional. In this case, they may be covered by the general term "polyols". The polyol may for example be a polyacrylate polyol, a polyester polyol, a polyether polyol, a polyurethane polyol, a polyurea polyol, a polyester-polyacrylate polyol, a polyester-polyurethane polyol, a polyurethane-polyacrylate polyol, a polyurethane modified alkyd, a fatty acid modified polyester-polyurethane polyol, and mixtures of said polyols. Preference is given to polyacrylate polyols, polyester polyols and polyether polyols.

Here, use may be made of at least one polymer which cures in the presence of isocyanate and/or oligoisocyanate groups, very preferably of at least one corresponding polyurethane and/or at least one corresponding polyurea (for example, the so-called "polyaspartic acid binders"). Polyaspartic acid binders are components converted by the reaction of amino-functional compounds, especially secondary amines, with isocyanates. Particularly suitable, if at least one polyurethane is used, are those polyurethane-based resins which can be prepared by polyaddition reactions between hydroxyl-containing components, such as polyols, and at least one polyisocyanate (aromatic and aliphatic isocyanates, di-, tri-and/or polyisocyanates). Generally, a stoichiometric conversion of the OH groups in the polyol to the NCO groups in the polyisocyanate is required here. However, the stoichiometric ratio used may also vary, as the polyisocyanate may be added to the polyol component in an amount such that "over-crosslinking" or "under-crosslinking" may be present. If an epoxy resin, i.e., an epoxy-based resin, is used, suitable ones are preferably epoxy-based resins prepared from glycidyl ethers, which have terminal epoxy groups and have hydroxyl groups as functional groups within the molecule. These are preferably reaction products of bisphenol A with epichlorohydrin and/or bisphenol F with epichlorohydrin, and mixtures thereof, which are also used in the presence of a reactive diluent. Curing or crosslinking of such epoxy-based resins is usually achieved by polymerization of the epoxy groups of the epoxy ring, by polyaddition in the form of a stoichiometric addition reaction of other reactive compounds (as hardeners) with the epoxy groups, in which case it is therefore necessary to have one active hydrogen equivalent per epoxy group (i.e. one H active equivalent per epoxy equivalent curing), or by polycondensation of epoxy and hydroxyl groups. Examples of suitable hardeners are polyamines, especially (hetero) aliphatic, (hetero) aromatic and (hetero) cycloaliphatic polyamines, polyamidoamines, polyaminoamides, and also polycarboxylic acids and their anhydrides.

The concept of "radiation curing" has been described above with respect to coating composition (B1 a). The coating composition (B2a) can be cured by using a radiation source, preferably by using UV radiation. Therefore, (B2a) is preferably a UV radiation curable coating composition.

Therefore, (B2a) preferably has an unsaturated carbon double bond, and more preferably a (meth) acrylic group. To this end, coating composition (B2) may comprise any of the components described above in connection with (B1a) and which may be classified under components (a) and (d) of (B1a), such as, in particular, polyesters, polyethers, carbonates, epoxides, poly (meth) acrylates and/or polyurethane (meth) acrylates and/or at least one unsaturated polyester resin and/or mono-, di-and/or tri-functional (meth) acrylates.

When curing by means of (N) IR and/or UV light, the coating composition (B2a) preferably comprises at least one photoinitiator which is capable of being decomposed into radicals by light of the radiation wavelength, which radicals are then capable of initiating radical polymerization. In contrast, in the case of curing with electron radiation, the presence of such photoinitiators is not necessary. As photoinitiator, the same components can be used in the same amounts as described above for component (c) of coating composition (B1 a).

Furthermore, the coating composition (B2a) may comprise at least one further additive. In this case, the same components may be used in the same amounts as described above for components (B) and (e) of coating composition (B1 a).

More preferably, the coating composition used as the coating composition (B2a) is a coating composition having a (meth) acrylic group. Preferably, the coating composition (B2a) comprises at least one polyurethane (meth) acrylate. Furthermore, preferably, it comprises at least one photoinitiator.

Complexes of the invention (F1B1)

Another subject matter of the present invention is a composite (F1B1) consisting of a substrate (F1) and an at least partially embossed and at least partially cured coating (B1) which can be prepared by at least partially curing by means of radiation curing an at least partially embossed coating composition (B1a) applied to at least a part of the surface of the substrate (F1), wherein the coating composition (B1a) is a radiation-curable coating composition comprising:

at least one component (a) in an amount of 40 to 95% by weight,

as component (b) at least one additive in an amount of 0.01 to 5% by weight,

at least one photoinitiator as component (c) in an amount of from 0.01 to 15% by weight, and

at least one component (d) containing at least one carbon double bond in an amount of from 0 to 45% by weight,

and wherein component (a) comprises at least 3 structural units of formula (I), each of which is different from or at least partially identical to each other:

wherein:

radical R¹In each case independently of one another is C₂-C₈Alkylene oxideThe base group is a group of a compound,

radical R²In each case independently of one another, H or methyl, and

the parameters m are each, independently of one another, an integer parameter of from 1 to 15, with the proviso that the parameter m in at least one structural unit of the formula (I) in component (a) is at least 2.

All of the preferred embodiments described above in connection with the process of the invention, in particular in connection with the coating composition (B1a) and the substrate (F1) and coating (B1) used therein, are also preferred embodiments in connection with the compound (F1B1) of the invention.

The complexes (F1B1) according to the invention can preferably be obtained by carrying out the above-described process steps (5) to (8) of the process according to the invention. The substrate (F1) is preferably a film web, more preferably a continuous film web.

Use of

Another subject of the present invention is the use of the composite (F1B1) of the invention as an embossing die (P2) of an embossing tool (P2) to transfer an embossed structure onto at least a part of the surface of a coating composition (B2a) or at least a part of the surface of a coating composition (B2a) applied at least partially onto a substrate (F2), preferably onto a substrate (F2) coated with a coating composition (B2a), preferably within the process of the invention.

All of the preferred embodiments described above in connection with the process according to the invention and the complexes according to the invention (F1B1) are also preferred embodiments in connection with the above-described use of the complexes according to the invention (F1B 1).

Here, the coating composition (B2a) is preferably a radiation-curable coating composition.

Measurement method

1.Determination of non-volatile Components

The nonvolatile content (solids or solids content) was determined in accordance with DIN EN ISO 3251 (date: 6.2008). The method comprises weighing 1g of the sample into an aluminium pan which has been previously dried, drying the sample in a drying cabinet at 125 ℃ for 60 minutes, cooling it in a desiccator and then weighing it again. The residue corresponds to the non-volatile fraction relative to the total amount of sample used.

2.Measurement ofMoulding precision

The shaping accuracy was determined by a commercially available Atomic Force Microscope (AFM) and using a commercially available cantilever. Thus, with AFM, it is possible to compare the surface topography with a defined lattice structure (e.g., the surface topography of the embossing tool P1 with a depth of, for example, 140nm and a period of, for example, 430 nm) with the surface topography of the master film after embossing (B1F 1). In this case, the embossing tool is deliberately damaged at a specific location in order to define the reference point. By means of this reference point, the same regions of the reference and the replica can be investigated and compared with one another. The shaping accuracy defines how high the precision with which a particular reference structure can be transferred, for example from the embossing tool P1 to the master film (B1F 1). For example, if the investigation region of the embossing tool P1 is characterized by a lattice-like structure with a depth of 140nm, this reference depth is compared to the corresponding height of the structure determined on the mother film (B1F 1). Here, the percentage change corresponding to the shaping precision is defined as:

here,. DELTA.h corresponds to the percentage change, h_mCorresponding to the height of the structure in the investigation region of the mother film, and h_rCorresponding to the respective depths of the structures of the investigation region of the embossing tool. This percentage change, in other words the shaping accuracy, is also called "shrinkage". The smaller the value of Δ h, the better the shaping accuracy.

3.Determination of flow time

The flow time is determined in accordance with DIN EN ISO 2431 (date: 3 months 2012). The method comprises measuring the flow time at room temperature (20 ℃) with the aid of a 4mm flow cup (number 4).

4.Determination of double bond conversion

After curing the sample in question, the double bond conversion (DB conversion) was determined by ATR-IR spectroscopy. By means of the ATR-IR spectroscopy technique, an IR spectrum is recorded at the contact position of the circular reflective crystal with the substrate. The contact locations have a diameter of about 200 μm and the reflective crystal used is a germanium crystal.

The starting materials used to calculate the double bond conversion include the corresponding wet samples of the samples. Through 810cm^-1The decrease in band intensity to calculate the DB conversion ratio. The band used for normalization was 1730cm^-1The percentage of double bond conversion is calculated by the following formula:

here, I_810cm-1The solidified layer is 810cm^-1Normalized intensity of (A), I_{Reference-810 cm-1}Is a corresponding wet sample at 810cm^-1The normalized intensity of (c). A double bond conversion of > 90% was classified as sufficient.

5.Determination of the adhesion

The adhesion was determined by a cross-hatch test according to DIN EN ISO 2409 (date: 6 months 2013). In this test, the adhesion of the coating in question to the substrate was checked in two measurements. A cross-hatch tester with a 2mm hatch spacing of Byk Gardner was used manually. Subsequently, Tesa tape 4651 was pressed onto the damaged area and peeled off to remove the delaminated area. Evaluation was performed based on characteristic values of 0 (minimum delamination) to 5 (very high delamination). An average value of at least 3.5 was classified as sufficient.

6.Determining a copy success rate

The success rate of replication was determined visually, where the percentage fraction of successful replication area was determined. Here, the range is 0-100% of the area of successful replication. If 100% of the area is not replicated, this means that the corresponding area fraction cannot be removed from the embossing die, in other words the coating B1 remains partially adhered to the embossing tool P1 in the form of B1F1, or the coating B2 remains partially adhered to the master film B1F 1.

Inventive and comparative examples

The following examples of the invention and comparative examples are intended to illustrate the invention but should not be construed as imposing any limitation thereon.

Unless otherwise indicated, amounts in parts are parts by weight, amounts in percentages are percentages by weight in each case.

1.Compounds and materials therefor

GN-a commercially available PET film with a layer thickness of 125. mu.m.

UA 9033(L UA 9033) -aliphatic urethane acrylates from BASF SE, may be used as component (d).

Hexanediol diacrylate (HDDA) -may be used as component (d).

395(SR 395) -isodecyl acrylate, available from Sartomer, is useful as component (d).

502(SR 502) -9-fold ethoxylated TMPTA (trimethylolpropane triacrylate) obtained from Sartomer502 may be used as component (a).

499(SR 499) -6-fold ethoxylated TMPTA (trimethylolpropane triacrylate) obtained from Sartomer can be used as component (a).

454(SR 454) -3-fold ethoxylated TMPTA (trimethylolpropane triacrylate) obtained from Sartomer, may be used as comparative component (a).

TMPTA (trimethylolpropane triacrylate) -may be used as comparative component (a).

GPTA (glyceryl propoxy triacrylate) -3-fold propoxylated glyceryl triacrylate may be used as comparative component (a).

184(I-184) -a commercially available photoinitiator from BASF SE, may be used as component (c).

TPO-L (I-TPO-L) -a commercially available photoinitiator available from BASF SE, can be used as component (c).

TPO (I-TPO) -a commercially available photoinitiator available from BASF SE, can be used as component (c).

Rad 2500(TR 2500) -lubricating and antiblocking additive (silicone acrylate) from Evonik, useful as component (b).

Byk-SILCLEAN 3710(BS 3710) -surface additive (polyether modified polydimethylsiloxane with acrylic functionality) from BYK Chemie GmbH can be used as component (b).

2. Examples of the embodiments

2.1 preparation of the coating composition (B1a) and of the corresponding comparative coating composition

Coating compositions were prepared according to tables 1a and 1b below. Coating compositions E1a to E7a are of the invention. Coating compositions V1a to V5a are comparative coating compositions. In the case of preparations E1a to E3a and V1a to V5a, the flow times determined at room temperature (20 ℃) were from 26 to 172 seconds.

Table 1 a:

table 1b:

2.2 preparation of mother Membrane (B1F1) Using E1a to E3a and V1a to V5a

A number of different master films were prepared using a roll-to-plate embossing apparatus with a nickel embossing tool P1 carrying the desired positive structure. For this purpose, each of the above coating compositions E1a to E3a and V1a to V5a was applied onto P1, and a PET film (F1) was applied thereon (F1)GN). The resulting stack of film and the respective coating composition is then passed under a press roller and the coating composition is at least partially cured by means of a UV-LED lamp, while still the embossing device is in contact with the respective stack of coating composition. In this case, the lamp used was a 365nm, 6W UV-LED lamp (100% lamp power, 2 m/min, 2 passes) from Easytec. Subsequently, the at least partially cured coating is separated together with the film from the embossing device (having a negative-type structure compared to P1) to give a structured film (master film). The master film was then post-exposed with a UVA lamp (Panacol-Elosal UV F-900).

Further, a master film was prepared using a roll-to-roll embossing apparatus having a nickel embossing tool P1 with the desired positive structure. For this purpose, the above-mentioned coating composition E1a was applied to a PET film (F1) (F1)

GN) and guided by means of a press roller to an embossing tool P1. While the embossing apparatus is still in contact with the coating composition, the coating composition is at least partially cured by a UV-LED lamp. In this case, the lamp used was a 365nm, 6W UV-LED lamp (100% lamp power, 5 m/min) from Easytec. Subsequently, the at least partially cured coating is separated from the embossing device together with the film having a negative-type structure compared to P1, resulting in a structured film (master film). The master film was then post-exposed with a UVA lamp (Panacol-Elosal UV F-900).

2.3 preparation of mother films (B1F1) using E4 a-E7 a

Using a positive type having the desired positive typeStructured nickel embossing tool P1 produced many different master films. For this purpose, the above-described coating compositions E4a to E7a were each applied to P1, and a PET film (C: (B))

GN) is applied thereto. The resulting stack of film and the respective coating composition is then pressed with a rubber roller and the coating composition is at least partially cured by means of a UV-LED lamp, while still the embossing device is in contact with the coating composition of the respective stack. In this case, the lamp used was a 365nm, 6W UV-LED lamp (100% lamp power, 2 m/min, 2 passes) from Easytec. Subsequently, the at least partially cured coating is separated from the embossing device together with the film having a negative-type structure compared to P1, resulting in a structured film (master film).

2.4 mother film obtained

In the manner described in sections 2.2 and 2.3, sets of mother films (E1F1 to E7F1 and V1F1 to V5F1) were obtained, which were additionally embossed differently depending on the characteristics of the positive type structure. In this case, nickel embossing devices with different positive structures are used, which have in particular:

nanostructures (lattice-like structures with a period of 430nm and a depth of 140 nm; the corresponding coating compositions are applied to the PET film used in a layer thickness of 5 to 10 μm),

microstructures A (two-dimensional triangular structures with a width and height of 33 μm and a spacing between the structures of 35 μm; the corresponding coating composition is applied to the PET film used in a layer thickness of 20 μm),

microstructures B (continuous two-dimensional triangular structures with a width of 43 μm and a height of 10 μm, the corresponding coating compositions being applied to the PET film used in a layer thickness of 20 μm), or

Microstructures C (two-dimensional triangular structures with a height of 80 μm and a spacing between the structures of 115 μm, the corresponding coating composition being applied to the PET film used in a layer thickness of 110 μm).

The master film with nanostructures was used to determine the shaping accuracy, double bond conversion and adhesion. In the case of those mother films which were prepared using one of the coating compositions E1A to E3A and V1A to V5A (see point 2.5 below) and also used as an embossing die described below at point 2.6, the mother film having the microstructure a was used to determine the replication success rate. In the case of those mother films which were prepared using one of the coating compositions E4a to E7a (see point 2.5 below) and which also served as the embossing die described below at point 2.6, the mother film having the microstructure B was used to determine the replication success rate. A master film with microstructure C was used as the embossing die, as described below at point 2.7. To prepare this master film, coating composition E1a was used, and accordingly a master film E1F1 with microstructure C was obtained.

2.5 study of mother Membrane

Table 2 below summarizes the studies performed. The study was carried out according to each of the above methods. The symbol "-" in the table indicates that no specific study was performed.

Table 2:

mother film	DB conversion (%)	Adhesion property	Success rate of replication (%)	Moulding precision (Δ h,%)
					E1F1	92	3.5	100	4
E2F1	90	0.5	100	4
					E3F1	95	2.5	-	4
V1F1	93	5	100	3
					V2F1	85	1.5	85	2
V3F1	89	5	85	5
					V4F1	92	5	100	4
V5F1	87	5	85	29
					E4F1	-	-	100	-
E5F1	-	-	100	<1
					E6F1	-	-	100	-
E7F1	-	-	100	<1

The data indicate that adequate DB conversion was not achieved with V2F1, V3F1, and V5F1 (DB conversion < 90). When the DB conversion is too low, problems may occur in the embossing of the coating composition (B1a) and the subsequent coating composition (B2 a). In contrast, the parent films E1F1, E2F1 and E3F1 showed DB conversion of at least 90%.

In the case of V1F1 and V4F1, the DB conversion was indeed > 90%, but the adhesion obtained with these parent films, just as with V3F1 and V5F1, was insufficient (cross-hatch test evaluated on a scale of 5). If the adhesion of the mother coat on the PET film is insufficient, problems may occur in the embossing of the coating composition (B1a) and the subsequent coating composition (B2 a). In contrast, the mother films E1F1, E2F1, and E3F1 all showed good to sufficient adhesion.

Furthermore, the data also show that in the case of V2F1, V3F1 and V5F1, only a value of 85% was obtained in the evaluation of the replication success rate, since 15% of the respective coatings V2, V3 and V5 could not be removed from the embossing tool. In contrast, the studied mother films E1F1 and E2F1 showed 100% replication success rate.

With the exception of V5F1, all of the parent films studied showed sufficient shaping accuracy because very low shrinkage values were consistently obtained. Only in the case of V5F 1a shrinkage of 29% was obtained, which is not acceptable.

In summary, it can be said that only the mother films E1F1, E2F1 and E3F1 provided good results in terms of all the properties studied (DB conversion, adhesion, shaping accuracy and replication success rate).

2.6 use of the mother film as an embossing die to make embossed product films

Then, the mother films having the microstructures a or B respectively obtained were each used as an embossing die of an embossing tool. For this purpose, the master film is used in a roll-to-plate embossing apparatus. The coating composition (B2a) was applied to the corresponding master film at a wet layer thickness of 20 μm. Further, a PET film (B) as a base material F2GN) with the coating composition (B2 a). The resulting stack of film and coating composition (B2a) then passed under a pressure roller and the coating composition was at least partially cured by a UV-LED lamp (B2a) while the embossing apparatus was still in contact with the coating composition of the respective stack. In this case, the lamp used was a 365nm, 6W UV-LED lamp (100% lamp power, 2 m/min, 2 passes) from Easytec. Subsequently, the at least partially cured coating B2 was separated together with the film F2 having the desired final embossed structure from the embossing die of the embossing tool, in other words from the particular parent film used, and a structured product film was obtained (B2F 2).

The coating composition (B2a) used is a commercially available radiation-curable coating composition comprising at least one urethane acrylate, at least one photoinitiator and commercially available additives.

Table 3a below summarizes the results of the studies on successful replication on the resulting product films, taking into account the specific master film used for embossing. The symbol "-" in the table indicates that no specific study was performed.

Table 3 a: replication success rate of embossed structure of product film

The mother film used	Success rate of replication (%)
		E1F1	100
E2F1	100
		E3F1	-
E4F1	100
		E5F1	100
E6F1	100
		E7F1	100
V1F1	42*
		V2F1	100
V3F1	85
		V4F1	100
V5F1	100

Mean of two determinations

The data show that in the case of using V1F1 and V3F1 as embossing dies, only values < 100% were obtained when evaluating the replication success rate, since in these cases 15% or 58% of the coating B2 could not be removed from the coatings V1 and V3 of the respective parent films. In contrast, when the investigated master films E1F1, E2F1 and E4F1 to E7F1 were used as embossing dies, a 100% replication success rate of the coating B2 of the product film was achieved.

2.7 other uses of mother film as embossing die to make embossed product film

The obtained mother film (E1F1) having the microstructure C was used as an embossing die. The coating composition (B2a) was applied to the master film at a wet layer thickness of 100 μm. Further, a PET film (B) to be a base material F2GN) was contacted with and pressed against coating composition (B2 a). The resulting stack of film (F1), coating (B1, i.e. E1), coating composition (B2a) and film (F2) was cured at room temperature (23 ℃) for 24 hours. Subsequently, the at least partially cured coating (B2) was separated together with the film (F2) having the desired final embossed structure from the embossing die, in other words from the parent film (E1F1) used together with the microstructures C, thereby obtaining a structured product film (B2F 2).

The coating composition (B2a) used was a commercially available heat-curable two-component epoxy resin (Epofix from Struers GmbH). The mixing ratio of the component 1 and the component 2 is 9: 1. Component 1 comprises at least one bisphenol epichlorohydrin. Component 2 comprises at least one polyamine.

Table 3b below summarizes the results of the replication success rate study on the resulting product film, considering the master film for embossing.

Table 3 b: replication success rate of embossed structure of product film

The mother film used	Success rate of replication (%)
		E1F1	100

In the case of using the mother film E1F1 as an embossing die, a 100% replication success rate of the product film coating B2 was obtained even when a heat-curable coating composition was used as the coating composition (B2 a).

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Method for transferring an embossed structure to a surface of a coating device and composite structure usable as an embossing die

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