RU2718932C2 - Method of creating surface effects in coating, in particular in uv-curable layers, device for hardening coating fluids, device for applying coating fluid medium, coating fluid medium, article - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of creating surface effects in a coating which is hardened by energy-intensive corpuscular radiation, particularly UV radiation. Method of creating surface effects in a coating which is capable of solidification by energy-intensive corpuscular radiation, in particular UV radiation, involves depositing a coating onto a base of a fluid, for example a radically curable, particularly a UV-curable lacquer. Coating fluid medium is designed so that the reactivity on the surface of the deposited coating film is purposefully different from the reactivity in the volume of the applied coating film. Method also includes irradiation of coating with energy-intensive corpuscular radiation, thus at first stage only surface coating layer is processed, wherein said surface layer has thickness of 10 nm to 1 mcm, and at second step coating is cured throughout its thickness. Device for hardening coating fluids, which are capable of hardening with energy-intensive corpuscular radiation, in particular UV radiation, in which curing is carried out in two steps. Power introduced by means of the device into the coating for its hardening can be controlled so that at the first stage only the surface layer of the coating is treated, and at the second stage the coating is cured along the whole thickness, and the above surface layer has thickness from 10 nm to 1 mcm. Device for creating surface effects on at least one portion of base coated with coating, made with possibility of hardening by energy-intensive corpuscular radiation, in particular UV radiation, comprises mainly device for location of base, facility for transportation of base between separate working positions, device for application of coating fluid medium on base. Device can be made with the possibility of application of the fluid medium of the coating along the whole area of the base surface or only in its one section. Device for creation also includes device for hardening of coating. Hardening is carried out in two steps. Power introduced by means of the device into the coating for its curing can be adjusted mainly with the possibility of processing at the first stage only the surface layer of the coating. Surface layer has thickness from 10 nm to 1 mcm, and at second stage - curing of coating throughout thickness. Besides, the device for creation includes mainly the device for removal of the base, and also mainly the device of the plant control. Fluid medium of coating is made with possibility of hardening by energy-intensive corpuscular radiation, in particular UV radiation, in particular due to radical polymerisation, and also available to micro-folding process. Micro-folding occurs due to irradiation of surface layer of applied coating, for example due to exposure to UV-C-radiation with wave length of more than 240 nm, thus, at first stage only surface coating layer is treated. Surface layer has thickness of 10 nm to 1 mcm, and at the second stage, the coating is cured over its entire thickness. Article for use in printing industry, and/or for aviation, and/or for water transport includes a base and a coating applied thereon. Coating in at least one area includes a surface layer with micro folding, having thickness from 10 nm to 1 mcm.

EFFECT: technical result of group of inventions is simplification and cost reduction when creating surface effects with provision of various optical and/or tactile-sensor effects.

33 cl, 13 dwg

Description

FIELD OF THE INVENTION

The invention relates to a method for creating surface effects, in particular in UV-curable layers, due to micro-folding, as well as to a device for manufacturing such layers and the product obtained according to the invention.

Another aspect of the invention relates to the creation of curable energy-intensive particle radiation, for example UV radiation, coating fluids that are processed by the proposed method.

State of the art

The curing of organic polymerizable coatings using energy-intensive particulate radiation, such as UV radiation, has been an industrial process for many years. In particular, it is also known how, by choosing a suitable coating system, a matte or shiny surface can be obtained.

In the framework of the present invention, the gloss of the varnish or lacquered surface is indicated in accordance with DIN 67530 or ISO 2813, and the gloss units are indicated when viewing the corresponding surface at an angle of 60 °. A high-gloss surface is a surface with 70-100 GE (GE = gloss units), a half-gloss surface is a surface with 45-70 GE, and a semi-gloss surface is a surface with 20-45 GE. Matte surface has less than 20 GE.

Difficulties arise, however, when, when using the system, coatings must create both matte and glossy areas, for example, to indicate special functional areas of the surface. It is also known to create surfaces that must have certain structures or a certain haptic, i.e. provide a special tactile sensory perception. Also in the case of these effects, the simultaneous creation of zones of different visual or structural manifestations using the same coating system is currently possible only with high equipment costs.

Different haptic and / or visual properties, such as matte / glossy effects, can be created using the same coating system in different ways. A simple possibility is to coat the substrate previously pre-treated in different ways. An example of this is UV varnishing of a substrate that has previously been treated with a poorly wettable oil printing varnish or special printing ink. The subsequent coating in this case creates a repulsion in the pre-treated areas and, therefore, a matte surface.

This effect is known in Asian countries as Chemical Embossing. In European countries, this method is called “Drip-Off-Lackierung” (hybrid varnishing).

Subsequent, sometimes different processing of a uniform film by means of a template is known.

In practice, in most cases, and the specialist is also well aware of the change in the degree of haze inside the surfaces coated with matte varnish, depending on the thickness of the layer. So, for example, particles of the matting agent in the thicker varnish layers partially no longer appear on the surface, as a result of which the film in these areas seems less opaque. This effect can also be purposefully used.

Methods are also known in which coatings are matted after application to the surface of the resulting coating film after application. In the simplest case, this can be done by etching or sandblasting. Also here, using a template, you can create a pattern on the surface.

A similar effect can also be created in a still liquid coating before curing if (partial) roughness is created using energy-intensive radiation.

Thus, DE 102006042063 A1 describes a method for controlling the degree of gloss of surfaces that were obtained by coating with UV curable varnishes or electron beam curing varnishes. In this case, first, short-wavelength monochromatic UV radiation affects the coating applied to the substrate, so that polymerization and crosslinking only occur in the surface layer of the coating. At the second stage, electromagnetic radiation with a different, longer wavelength acts on the coating, as a result of which crosslinking occurs over the entire thickness of the applied coating, and the layer cures accordingly. Thus, in the surface layer, such induced crosslinking causes micro folding, which is fixed by subsequent curing of the entire layer. Due to a suitable choice of curing parameters, it is thus possible to create both high gloss and matte surfaces by means of a coating system.

In the framework of the invention, micro-folding is understood as the following phenomenon: the surface layer of the applied coating fluid is cured in the first stage into a skin-type layer, i.e. into a layer with a harder or more viscous fraction close to the surface. Due to shrinkage during curing, this surface layer is compressed during curing. As a result, structuring occurs, which is due to the fact that at least on one part of the surface of the coating there is a local change in the thickness of the coating, so that the thickness fluctuations lie in at least a unique micrometer range. In particular, the surface layer may be folded. In a second step, the applied coating fluid cures throughout the volume.

Excimer emitters are used as sources of monochromatic radiation, which can cause micro-folding due to crosslinking of the surface layer. In particular, monochromatic radiation with wavelengths of 172 or 222 nm is used.

However, the disadvantage of using excimer emitters for micro folding is that in order to ensure uniform matting, the radiation must occur in an inert gas atmosphere, since oxygen inhibition known for radically curable coatings worsens the desired surface reaction. For example, WO 2007/068322 A1 describes a device suitable for implementing the micro-folding method of UV curable varnishes, in which the irradiation conditions remain stable. For this, the radiation sources are designed so that a stable atmosphere of inert gas is provided and the inert gas is used simultaneously to cool the emitter, thereby increasing the service life of excimer lamps.

An improvement of the above methods is described in EP 2418091 A1. Here, a method is described in which micro-folding occurs only on appropriately selected portions of the varnish surface, while in other areas of the varnish surface a smooth surface is obtained. For this, the lacquer surface is exposed only to appropriately selected areas to the short-wave electromagnetic radiation necessary for micro-folding, for which the radiation source is equipped with a template or mask, so that the desired, only partial exposure of the surface occurs. In this way, a coating is obtained which has at least one zone with a matte or micro-folded surface and at least one zone with a smooth surface, and the zones do not differ or differ only insignificantly with respect to the thickness of their layer.

Excimer radiation is also used to create micro-folding in the method described in EP 2418091 A1.

The mechanism of micro-folding described in the above sources of information is based on a combination of a small depth of radiation penetration and, therefore, close to the surface of the impact with the property of the radially cured system to undergo shrinkage during curing during the polymerization reaction. Both of these effects create a film floating on the still liquid coating material that develops as a result of shrinkage during curing. In the second curing step then carried out, the still liquid intermediate zone is also cured and bonded to the substrate and the folded surface film.

Known methods for creating micro-folded matte surfaces or surfaces with special optical effects or a specific tactile-sensory perception have, therefore, in general, the disadvantage that an excimer emitter must be used to create a micro-folded structure. Even if, as in EP 2418091 A1, light with a wavelength of up to 300 nm could be used to create micro-folding, nevertheless, a monochromatic light source is always required, which differs from the second light source necessary for complete deep curing of the coating. The reason for this is that the excimer radiation in the coating solutions or varnishes is strongly absorbed, as a result of which only a thin film, for example, several microns thick, is cured. Since the varnish layer is generally thicker than this corresponds to the penetration depth of the laser radiation, for curing the varnish layer throughout its thickness, it is necessary to use a second emitter with a different wavelength for this volume curing. This leads to complex methods with high equipment costs.

Thus, there is a need for an inexpensive, simplified method of creating surface effects in coatings due to micro-folding, in particular in methods by which these surface effects are only partially created in a coating. In addition, various optical and / or tactile-sensory effects must be achieved in different areas of the coating surface.

Disclosure of Invention

The objective of the invention is to provide a method of simplified, inexpensive matting of varnish surfaces due to micro-folding, in particular a method by which only surface areas could be purposefully matted or provided with optical or tactile-sensory properties. In one embodiment, different surface effects can be created in different areas of the coating, and the thickness of the coating layer between the individual zones can be different.

Other aspects of the invention relate to devices for implementing the proposed method, thus manufactured articles and coating fluids available to such a method.

The objective of the invention is solved in an unexpected way through the method according to p. 1, devices according to independent p. 19, 23 and the coating fluid of claim 24. Another aspect relates to a product thus manufactured with microfolded surfaces according to claim 29. Preferred options are described in the corresponding dependent claims.

The method of creating surface effects in a coating cured by energy-intensive particulate radiation, in particular UV radiation, includes the following steps:

- at the first stage, a coating is applied to the fluid base, for example, radically curable, in particular UV curable, varnish. Moreover, the coating fluid is made so that the reactivity on the surface of the applied coating film is purposefully different from the reactivity in the volume of the applied coating film,

- at the second stage, the coating is irradiated, and mainly UV-C radiation with a wavelength of 240 nm or more is introduced into the surface layer of the coating.

The method is based, therefore, on the same principle of micro-folding, achieved by excimer radiation and subsequent curing with UV radiation with a longer wavelength or electronic radiation. The advantage of the proposed method, however, is that the reactivity of the surface is set to be reasonably different from the reactivity of the volume. Thus, using UV radiation with a longer wavelength, for example UV-C radiation of a standard medium pressure mercury emitter, it is possible to create micro-folding on the surface. The targeted reactivity of the surface of the deposited coating film and the reactivity of the coating volume further lead to the fact that the effect depends on the thickness of the layer. So, thin layers in the proposed process remain glossy, and thicker layers are matted.

Another advantage of the proposed method lies in the fact that the curing reaction of the surface and volume is initiated by an industry-standard mercury medium pressure transmitter. Thanks to this consumer, no additional investments or modifications to its installation are required.

The effect is based on adjusting the composition of the coating fluid so that the reactivity on the surface of the deposited coating film deliberately differs from the reactivity inside the deposited coating film.

This is achieved by the fact that two different photoinitiators are added to the coating fluid, which act differently, in particular in such a way that one photoinitiator increases the reactivity close to the surface area of the deposited coating film, and the other reduces the reactivity inside the deposited coating film.

In the prior art methods for UV curing, however, photoinitiators are already used. However, there is still a problem in that, when processing such UV-curable varnishes or fluids, the coatings under normal conditions, i.e. not in an inert gas, the chain reaction caused by photoinitiators is inhibited by oxygen. This leads to the fact that the zone of the applied coating film close to the surface cures less than its volume, and accordingly, the surface of the varnish layer has only a small hardness or, under certain conditions, still remains completely liquid.

To eliminate these difficulties, two solutions have been proposed in the prior art:

- processing in an inert gas atmosphere to thereby avoid the problem of a competing reaction of the formed radicals with oxygen, or

- increase the content of the photoinitiator.

However, both solutions have disadvantages. Thus, curing in an atmosphere of inert gas leads to an increase in equipment costs. If the content of the photoinitiator is increased, then the risk of migration of this photoinitiator from the cured coating increases, which is critical especially for food packaging. The increased migration is explained by the fact that, according to experience, not the whole photoinitiator is realized, but unrealized components always remain. Since the photoinitiators used are, as a rule, small mobile molecules, these particles remaining in the cured film can migrate from the film and, if packaged, go to its contents.

In addition, in this way it is only guaranteed that the area close to the surface and the internal volume of the applied lacquer layer cure substantially uniformly, i.e. the zone close to the surface has almost the same degree of crosslinking as in the inner volume of the lacquer layer. Stronger and earlier cross-linking of the zone close to the surface compared to the inner volume of the lacquer layer, causing micro-folding, with the help of these solutions, on the contrary, is impossible.

Therefore, in order to achieve earlier curing of the applied varnish film close to the surface of the surface, the use of an excimer emitter is still necessary. The surface reaction occurring using excimer radiation is based on the fact that this radiation causes, for example, the direct reactivity of the polymerizable acrylate monomer. However, the absorption of excimer radiation decreases exponentially with increasing penetration depth, so that only a zone close to the surface can be cured. For the reaction inside the applied varnish layer, on the contrary, it is also necessary to irradiate with UV light with a longer wavelength. Therefore, using methods known from the prior art that are carried out in two stages using excimer radiation and a second radiation source with a longer wavelength, it is possible, however, to purposefully cure the zone close to the surface with the formation of micro-folding. However, as mentioned above, these methods also lead to higher equipment costs.

The proposed method differs from the prior art methods, thereby, also in that it requires substantially less energy-intensive radiation than before to create micro-folding of the surface layer and surface effects. For example, UV radiation with a wavelength of 240 nm or more is already sufficient to create micro-folding, while excimer emitters with wavelengths of 172 and 222 nm have been used so far, with only a wavelength of 172 nm being suitable to create radicals without the use of photoinitiators. Such complex devices in the proposed method are no longer needed. In contrast, other radiation sources may be used in the proposed method.

In one embodiment, the surface layer has a thickness of 10 nm to 1 μm.

According to one embodiment, the irradiation takes place in two stages such that a lower UV dose is emitted at the first stage and micro-folding is created, and at the second stage the film is completely cured, with longer wavelength UV radiation, for example a UV emitter, being used at both stages of curing medium pressure.

According to another embodiment, it is also possible to achieve at the first stage of irradiation both micro-folding and deep curing of the film. For this, the coating material is accordingly made, in particular, in such a way that the absorption of UV radiation varies over the thickness of the layer of the coating agent.

Preferably, the surface layer is irradiated over the entire area. The creation of different effects in places with respect to gloss and haptic is achieved by preliminary creating different layer thicknesses in different ranges. So, in the range of layer thicknesses from 1 to 10 μm, for example, a smooth surface without micro-folding is obtained, and in the range of layer thicknesses of more than 12 μm micro-folding occurs.

According to another embodiment, irradiation occurs in at least one area such that only in this treated area are surface effects due to micro-folding, and at least one untreated area results in a smooth, non-micro-folding surface.

According to one preferred embodiment, only local irradiation of the surface layer occurs to create micro-folding in at least one area by means of a mask or template that / which shades the emitter zones, or by scanning the surface of the coating with local resolution.

Preferably, the scanning takes place due to the fact that the scanning head passes line by line the surface, the line is divided into individual image points or pixels, and each line is attached to one stroke of the scanning head.

According to another preferred embodiment, various surface effects occur in different areas of the coating.

Preferably, the coating fluid is irradiated in an inert gas atmosphere, preferably in a nitrogen atmosphere. Moreover, the residual oxygen content is less than 5000 ppm, preferably less than 1000 ppm or particularly preferably less than 500 ppm.

Preferably, the coating fluid is applied by means of a printing method, for example intaglio printing, flexographic printing, silk screen printing, pad printing or inkjet printing, or by rolling, dousing, squeezing, pouring, for example curtain or slot loading, immersion, spraying and / or centrifugation.

Particularly preferably used inkjet technology. In this way, it is especially easy to achieve different thicknesses of the coating material layer in different areas of the surface in a single pass. For example, here, too, due to appropriate screening and applying only very small layer thicknesses, preferably less than 2 microns, and also taking into account that the applied droplets do not merge, a coating with a matte surface can be applied. In areas with layer thicknesses where droplets join into the film, however, the layer thickness lies below the critical threshold, the surface appears glossy, and in areas above this critical threshold due to micro-folding, a matte effect is achieved. At the same time, all three of these different zones have different haptics. It differs not only in different layer thicknesses (relief effect, Braille structures, replacement of blind embossing by applying varnish), but also in modified friction resistance of different zones. Micro fold zones are distinguished, for example, by very low frictional resistance, while very smooth zones, on the contrary, can have an almost sticky effect when held through them by hand. Very thin matte structures, on the contrary, have very low friction resistance, however, in contrast to micro-folding zones, they are rather rough to the touch, and micro-folding zones, in contrast, are very smooth and soft to the touch.

According to another embodiment, the degree of gloss of the coating at the viewing angle according to DIN EN ISO 2813 is in the areas where the surface layer is illuminated to create micro-folding, after curing the entire layer of 0.1-80 GE. Preferably, the gloss level is 0.1-50 GE, very preferably 0.1-20 GE, and particularly preferably 0.1-10 GE, and this gloss level is determined according to DIN EN ISO 2813.

The invention further relates to a device for curing coating fluids, for example varnishes, which are cured by energy-intensive particle radiation, in particular UV radiation. In this case, curing occurs in two stages, and the power introduced by the device into the coating for curing is adjusted in such a way that only the surface layer of the coating is processed in the first stage, and in the second stage, the coating cures throughout the entire thickness.

One possible option includes the implementation of the curing device so that due to micro-folding by means of excimer emitters, inert gas cures in the atmosphere. The inert gas is preferably nitrogen. An inert gas atmosphere can help maintain micro-folding in the case of less suitable coating solutions, since the oxygen inhibition mentioned above, even with a suitable composition, worsens the reaction on the surface. If this deterioration decreases in an inert gas, then the surface reaction can proceed more efficiently, which can support the formation of micro-folding.

According to one embodiment, the device for curing the layer is designed so that first the surface layer is illuminated on one surface area, and then the coating cures over its entire area. Thus, only at least one coating area with a micro-folding surface occurs, while at least one other coating area has a non-folding, smooth surface.

Preferably, the device includes information means for controlling the cure of the coating. In particular, the information medium is configured to determine the power, dose and / or place of curing.

Another aspect of the invention relates to a device for creating surface effects in at least one portion of a substrate coated with a coating that is curable by energy-intensive particle radiation, in particular UV radiation, including the inventive device for curing the coating fluids as described above . The device includes:

- mainly a device for placing the base,

- means for transporting the base between the individual work positions,

- a device for applying a coating fluid to the substrate, and the device can be made in such a way that the coating fluid is applied over the entire area of the surface of the substrate or in only one portion thereof,

- a device (6) for curing the coating, wherein the curing takes place in two stages, and the power introduced by the device for curing the coating is adjusted mainly so that only the surface layer of the coating is processed in the first stage, and the surface layer has a predominantly thickness of 10 nm to 1 microns, and in the second stage, the coating cures over the entire thickness,

- mainly a device for extracting the basics, as well as

- mainly the installation control device, for example in the form of information tools, such as a computer, for controlling the stages of the installation, which controls the parameters of all stages of the method and ensures their interaction.

The installation control device preferably also includes means for reading parameters in the information format used in the printing industry, for example, JDF (Job Definition Format), and implementing them in the method steps. For example, such a tool may include a parameterization file recorded on the medium.

According to another embodiment, the device includes, respectively, at least one sensor, as well as an encoder and actuators, in order to sensoryly register the corresponding steps of the method and to realize them using computer controls by means of corresponding actuators.

Another aspect of the invention relates to a coating fluid suitable for implementing the proposed method. This is a fluid coating, cured by energy-intensive particulate radiation, in particular UV radiation, in particular due to radical polymerization, and available for the micro-folding process. In this case, micro-folding occurs due to irradiation of the surface layer of the deposited coating, for example, due to irradiation with UV-C radiation with a wavelength of more than 240 nm.

In general, a coating fluid suitable for implementing the proposed method has a composition, 100 parts of a liquid binder are present in 13 parts of a mixture of photoinitiators and / or crosslinking agents and / or activators for curing.

In the framework of the invention, photoinitiators are understood to mean substances that decompose as a result of light absorption, in particular UV light, to form reactive agents, for example, radicals or cations.

In one embodiment, photoinitiators that form radicals are used.

By crosslinking agents and / or activators, in the framework of the invention, it is to be understood substances which formulate polymerization reactions especially effectively, for example due to the fact that they are suitable for the formation of especially effective primary radicals. Another example of increased efficiency is the transfer of an inactive radical due to oxygen inhibition of a radical to a new primary radical. In the framework of the invention, the activator is also respectively a synergist, and it can be called so.

According to one embodiment, at least one tertiary amine is used as a crosslinking agent and / or activator. Preferably, this occurs, according to one embodiment, when a so-called type II photoinitiator is used as the photoinitiator. In a type II photoinitiator, radicals are formed due to the fact that a photoinitiator, such as benzophenone, takes away a hydrogen atom from a neighboring molecule. In contrast, in type I photoinitiator, radicals are formed directly due to the decay of the initiator molecule. An example of a type I photoinitiator is the Irgacure 1173 or Darocur 1173 photoinitiator, known under the trademark, containing 1-phenyl-2-hydroxy-2-methyl-1-propanone.

An acrylate-based binder is preferably used.

Next, a mixture of photoinitiators and / or crosslinking agents and / or activators is made up so that 1 part of type I photoinitiator, 6 parts of type II photoinitiator and 6 parts of activator are added.

The synergist (or activator), respectively, together with type II photoinitiators overcomes oxygen inhibition and is used, in particular, for crosslinking under atmospheric conditions to provide and / or enhance the reactivity of the surface.

According to one embodiment, the coating fluid has the following composition:

40 parts HDDA (hexanediol diacrylate)

10 parts TMPTA (trimethylolpropane triacrylate)

50 parts DPGDA (dipropylene glycol diacrylate)

6 parts Irgacure 1173 or Darocur 1173

6 parts of H-methyldiethanolamine.

A deliberate difference between the reactivity on the surface of the applied coating film and the reactivity in the volume of the applied coating film is achieved, due to the fact that 1 part of the photoinitiator type I is used, here 1-phenyl-2-hydroxy-2-methyl-1-propanone , 6 parts of a type II photoinitiator, here benzophenone, and 6 parts of an activator, here N-methyldiethanolamine, per 100 parts of a liquid binder mixture (here including HDDA, TMPTA and DPGDA). By varying the proportions of the type I photoinitiator relative to the proportions of the type II photoinitiator, other targeted differences in the reactivity on the surface of the deposited coating film from the reactivity in the volume of the deposited coating film can be achieved.

The term "parts" means in the framework of the invention, respectively, mass fractions.

According to another embodiment, the coating fluid has the following composition:

80 parts of HDDA (hexanediol diacrylate)

20 parts TMPTA (trimethylolpropane triacrylate)

1 part Irgacure 1173 (or Darocur 1173)

6 parts benzophenone

6 parts of H-methyldiethanolamine.

A deliberate difference between the reactivity on the surface of the applied coating film and the reactivity in the volume of the applied coating film is achieved, due to the fact that 1 part of the photoinitiator type I is used, here 1-phenyl-2-hydroxy-2-methyl-1-propanone , 6 parts of a type II photoinitiator, here benzophenone, and 6 parts of an activator, here H-methyldiethanolamine, per 100 parts of a liquid binder mixture (here including HDDA and TMPTA) and, in contrast to the previous example, a more highly reactive binder mixture is used of By varying the proportions of the type I photoinitiator relative to the proportions of the type II photoinitiator, other targeted differences in the reactivity on the surface of the deposited coating film from the reactivity in the volume of the deposited coating film can be achieved.

Another example of a product that can be equipped with micro-folding by means of radiation from a medium pressure mercury emitter is coated with the following composition:

100 parts DPGDA (dipropylene glycol diacrylate)

6 parts Irgacure 1173 (or Darocur 1173)

6 parts benzophenone

6 parts of H-methyldiethanolamine.

A deliberate difference between the reactivity on the surface of the applied coating film and the reactivity in the volume of the applied coating film is achieved, due to the fact that 1 part of the photoinitiator type I is used, here 1-phenyl-2-hydroxy-2-methyl-1-propanone , 6 parts of a type II photoinitiator, here is benzophenone, and 6 parts of an activator, here is N-methyldiethanolamine, per 100 parts of a liquid binder (here including DPGDA). Used DPGDA as a difunctional binder forms a relatively soft film. Volume shrinkage is less pronounced compared to TMPTA-containing formulations. By varying the proportions of the type I photoinitiator relative to the proportions of the type II photoinitiator, other targeted differences in the reactivity on the surface of the deposited coating film from the reactivity in the volume of the deposited coating film can be achieved.

In another embodiment, micro folding can be achieved in only one curing step. To do this, for example, elastic aliphatic urethane acrylates should be added to the coating composition. A very good reactivity with a very pronounced effect is achieved with the following composition:

80 parts DPGDA (dipropylene glycol diacrylate)

20 parts Allnex Ebecryl 4491

1 part Irgacure 1173 (or Darocur 1173)

6 parts benzophenone

6 parts of H-methyldiethanolamine.

A targeted difference in reactivity on the surface of the applied coating film from reactivity in the volume of the applied coating film is achieved, due to the fact that 1 part of the photoinitiator type I is used, here 1-phenyl-2-hydroxy-2-methyl-1-propanone , 6 parts of a type II photoinitiator, here is benzophenone, and 6 parts of an activator, here is N-methyldiethanolamine, per 100 parts of a liquid binder mixture (here including DPGDA and Ebecryl 4491). By varying the proportions of the type I photoinitiator relative to the proportions of the type II photoinitiator, other targeted differences in the reactivity on the surface of the deposited coating film from the reactivity in the volume of the deposited coating film can be achieved.

Similar effects can also be achieved with BASF's Resin 250.

All of the mentioned compositions are about the main compounds, which, in order to achieve processability, can be supplemented by appropriate ones, which contribute to the spill and wetting of additives. However, these additives do not have any effect on the achievement of the desired effects. In addition, to achieve micro-folding, a layer thickness of at least 12 microns is required. In the range of 10-12 μm, micro folding is formed only unevenly (Fig. 1). Below 10 microns, the surface remains glossy, respectively.

The named compositions are characterized by very low viscosity during processing (70-120 s in the cup for leakage DIN 2), which allows their use in inkjet print heads. In this case, preferably a method can be applied that enables the simultaneous creation of zones with very different layer thicknesses.

However, the effect of micro-folding is in no way dependent on viscosity. It is also possible to create much more viscous compositions that can be applied in other ways. It is important to obtain a relatively higher reactivity on the surface than in volume. The photoinitiators used must have their maximum absorption in the UV-C range.

The effect of micro-folding can be prevented if photoinitiators of higher concentrations are added to the composition to cure the volume (for example,> 2% Irgacure 1173 with otherwise equal concentrations of photoinitiators and co-initiators in the composition can prevent the effect). The same is true if photoinitiators with a longer absorption wavelength at suitable concentrations are used for volume curing. So, micro-folding can be prevented by adding 1% TPO (triphenylphosphine oxide) to the mentioned compositions.

Another aspect of the invention relates to an article consisting of a base and a coating applied thereto. Moreover, the coating, at least in one area, has a surface layer with micro-folding, and the coating is formed from

40 parts HDDA (hexanediol diacrylate)

10 parts TMPTA (trimethylolpropane triacrylate)

50 parts DPGDA (dipropylene glycol diacrylate)

6 parts Irgacure 1173 (or Darocur 1173)

6 parts benzophenone

6 parts of N-methyldiethanolamine

and / or

80 parts of HDDA (hexanediol diacrylate)

20 parts TMPTA (trimethylolpropane triacrylate)

1 part Irgacure 1173 (or Darocur 1173)

6 parts benzophenone

6 parts of N-methyldiethanolamine

and / or

100 parts DPGDA (dipropylene glycol diacrylate)

1 part Irgacure 1173 (or Darocur 1173)

6 parts benzophenone

6 parts of N-methyldiethanolamine

and / or

80 parts DPGDA (dipropylene glycol diacrylate)

20 parts Allnex Ebecryl 4491

1 part Irgacure 1173 (or Darocur 1173)

6 parts benzophenone

6 parts of H-methyldiethanolamine.

Suitable substrate materials as the basis for the coating can be conventional materials used in the printing industry, for example paper, cardboard, laminated paper or laminated cardboard, polymer films, as well as corrugated cardboard substrates. For lamination, preferably polyolefin films are used, as well as PET, acetate or similar films.

It is the change in the haptic due to micro-folding, which due to the prevention of the so-called glass effect can cause, for example, a decrease in sliding friction, makes the method of interest also for completely different applications, in addition to the printing industry. These include coatings with low friction resistance for air as well as water transport. Compared to smooth surfaces, the adhesion of dirt, lime and bacteria to such surfaces is also reduced.

In combination with particularly flexible or even flexible binders, it can be used to create the so-called Soft-Touch varnish surfaces (soft touch).

Further, the degree of gloss in at least one area having micro-folding is preferably 0.1-50 GE, very preferably 0.1-20 GE, and particularly preferably 0.1-10 GE, when viewing angle according to DIN EN ISO 2813 .

Due to a suitable choice of coating materials, instead of micro-folding, the proposed method can also create an effect similar to an ice pattern or the effect of broken safety glass.

Brief Description of the Drawings

In the drawings depict:

- FIG. 1-3: different photos of samples with different micro-folding;

- FIG. 4, 5: devices for creating surface effects on substrates in accordance with embodiments of the invention;

- FIG. 6: product obtained by the proposed method;

- FIG. 7-13: a photo of coatings in accordance with embodiments of the invention.

The implementation of the invention

In the following detailed description of preferred simplicity options, not all features of the corresponding device in FIG. 4-6 are scaled. In addition, the term "energy-intensive corpuscular radiation" is also used in general terms for photons. In particular, in the UV region of the spectrum and, in general, in the direction of shorter wavelengths, photons have an increasing partial character.

In FIG. 1 as an example, shows a photo of a sample in which a coating agent available for micro-folding was applied with a layer with a thickness of only 10 μm. It can be seen that the micro-folding was uneven. So, in the left part of the photo micro folding is clearly visible, and in the right part of the sample micro folding is only very weakly expressed until it is almost completely absent.

In FIG. 2 as an example shows the surface of the sample obtained by the proposed method. The layer thickness here is 30 microns. Micro-folding here is very pronounced.

In FIG. 3 shows a strong increase in the surface area of the sample of FIG. 2. Also here, structures created due to micro-folding are very clearly visible.

In FIG. 4 schematically shows an embodiment of a device 1 for creating surface effects in at least one portion of a substrate provided with a coating that cures with energy-intensive particulate radiation, in particular UV radiation, the device including:

In FIG. 4 shows means for transporting the base 3 between separate work positions. This transport means is formed in the device 1 as an example by parts 21-23 and includes a first shaft or roll 21 on which the substrate 3 is wound or the printed material 3 is wound, for example paper, cardboard, laminated paper or laminated cardboard, polymer films, and also corrugated cardboard substrates, or a polyolefin film or a PET or acetate film.

The base 3 moves along arrow 25 (transport direction) through the device 1, the surface 31 of the material being printed or the substrate or base 3 to be sealed is directed to FIG. 4 up. Shaft 22 is an additional part of the transportation means.

The device 1 also includes a device 4 for applying a coating fluid to the base 3. A device for applying a coating fluid is described, for example, in document WO 2009/012996, the disclosed contents of which are also made by its object in the form of a coating unit, and according to the invention, the described device is used, however, it is preferable to smooth the film deposited on the surface of the substrate by means of the application unit, however, it is an optional unit that must be used to practice the invention.

In this case, the device 4 can be made so that the coating fluid is applied over the entire area of the surface 21 of the base 3 or only in one of its sections. Moreover, the application over the entire area of the surface 21 of the base 3 is preferable if the coating fluid is applied, which in the cured state also performs a protective function, for example, acquires anti-scratch properties. In contrast, only a partial application, i.e. applying the coating fluid only to the surface portion 31 of the substrate 3, it is preferable, for example, to purposefully highlight or mark a specific area of the substrate. In this way, displays can also be created, for example in the form of drawings or texts.

The device 1 further includes a device 7 for curing the coating. Curing of the coating occurs in two stages. The power introduced by the coating curing device 7 is predominantly adjusted so that in the first step only the surface coating layer is processed. Moreover, the surface layer has a thickness mainly from 10 nm to 1 μm. In a second step, the coating cures over its entire thickness. Preferably, device 7 comprises curing control information. In particular, the information medium is configured to determine the power, dose and / or place of curing.

Next, in FIG. 4 shows a device 6 for drying a coating. By means of this device, the volatile components of the coating fluid can be removed in the first step before curing. Such a device 6 is included in the device 1, however, only optionally. The device 1 may also include a device 8 for cooling the coated substrate after curing.

According to one embodiment, the device 1 may include an installation control device 5, for example, in the form of information means, for example, a computer, for controlling the operation steps of the installation, which mainly sensoryly records the relevant parameters of all the steps of the method, controls mainly with the help of the corresponding executive bodies, and thereby ensures their interaction.

The installation control device 5 preferably also includes means for reading parameters in the information format used in the printing industry, for example, JDF, and implementing them in the steps of the method. For example, such a tool may include a parameterization file recorded on the medium.

It is also possible that device 1, without limiting the example described here, includes several control devices that purposefully control individual devices.

According to one embodiment, the device includes, respectively, at least one sensor, as well as an encoder and actuators, in order to sensoryly register the corresponding steps of the method and, using computer control, to realize them by means of respective actuators.

Installation control device 5, according to one embodiment, is connected to devices included in device 1, for example, devices 4-7, preferably via suitable interfaces, for example 54-57.

In FIG. 5 schematically shows a device 1 according to another preferred embodiment. The device 1 includes a device 301 for placing a base, which contains various bases 3, of which not all are shown for clarity. From the device 301, individual substrates 3, which may include, for example, paper, cardboard, laminated paper or laminated cardboard, polymer films, as well as corrugated cardboard substrates, or a polyolefin film or a PET or acetate film, are transported by means of a conveyance between separate work positions through device 1.

The means for transporting the base 3 includes a first shaft 21, a second shaft 23 and an additional shaft 22, and various additional additional shafts 22 are included in the means for transporting. In addition, the means for transporting includes a conveyor belt 24 that connects both the shaft 21, 23, so that due to the rotation of at least one of the shafts 21, 23, the movement of the base 3 through the device 1 in the direction of the arrow 25 occurs.

The device 1 also includes a device 4 for applying a coating fluid to the substrate 3 and a device 7 for curing the coating.

The devices 6, 8 are shown below, which can serve, respectively, for drying the coating fluid and cooling the sealed base after curing, and in this case are only optional. Devices 4-7 can be connected to the installation control device 5 via the corresponding interface 54-57. Also, such an installation control device 5 with corresponding interfaces is only optionally included in the device 1.

It is also possible that several device 5 control devices 5 that control the individual devices 4-7 are included in the device 1 without limiting the example described here.

In addition, the device 1 includes, in this embodiment, a device 302 for removing the base 3.

In FIG. 6 schematically and not to scale depicts two articles 300, including a base 3, on the surface 31 of which (not shown) a coating 32 is applied. It has at least one section a surface layer with micro-folding.

At the top of FIG. 6 shows a product 300 with a coating 32 on the entire surface 31 (not shown) of the substrate 3. At the bottom of FIG. 6 shows the coating 32 only on the surface 31 (not shown) of the base 3.

The invention relates, therefore, to a method for creating surface effects in a coating that is cured by energy-intensive particulate radiation, in particular UV radiation, the method comprising the following steps: applying a coating fluid, for example radially curable, in particular UV curable, varnish , on the basis of, and the coating fluid is made so that the reactivity on the surface of the applied coating film is purposefully different from the reactivity in the volume of the applied coating film tiya, as well as to devices, in particular for implementing this method.

In FIG. 7 shows photographs of coatings in accordance with embodiments of the invention. In this case, we are talking about a total of eight coatings deposited on a black base. Individual coatings differ from each other in their fluid composition and / or layer thickness. While at the top of FIG. 7 rather receive matte coatings, i.e. coatings, rather with a low degree of gloss, at the bottom of FIG. 7 depicts coatings having, rather, a high degree of gloss. Moreover, the degree of gloss is a function of micro-folding, so that, for example, in the case of very strong micro-folding at a certain viewing angle, the coating may acquire a rather matte appearance.

To better illustrate the various effects that coatings can show in accordance with embodiments of the invention, FIG. 8-13 show photographs of individual coated samples.

In FIG. Figure 8 shows a coating in which micro-folding occurs in the form of a structure on a larger surface, approximately comparable to the so-called "dry cracks", which are formed, for example, upon drying of initially moist soils. In addition to the described structuring, the coating has a relatively high degree of gloss.

In FIG. 9 depicts a coating in which micro-folding is formed in the form of smaller structures, as a result of which it acquires, rather, a matte appearance.

In FIG. 10 depicts another coating in accordance with another embodiment of the invention. Also here, the coating has acquired a matte appearance, and here, in general, it seems even more matte compared to the coating in FIG. nine.

In contrast to FIG. 11 shows a coating that has a very high gloss, i.e. only a very small micro fold was obtained.

In FIG. 12 and 13 depict two samples having an effect like an ice pattern, i.e. give the impression of ice-covered glass. This effect is visible in the coating of FIG. 12, however, it is even more pronounced in the coating of FIG. 13.

Thus, it remains, in general, to state that by the method in accordance with embodiments of the invention various optical effects in the coating can be realized due to the micro-folding of the varnish surface.

Claims (42)

1. The method of creating surface effects in the coating (32), made with the possibility of curing by energy-intensive particulate radiation, in particular UV radiation, and the method includes the following steps: - applying to the base (3) a coating fluid, for example radically curable, in particular UV curable, varnish, the coating fluid being made so that the reactivity on the surface of the applied coating film is purposefully different from the reactivity in the volume of the applied coating film, - irradiating the coating (32) with energy-intensive corpuscular radiation, so that at the first stage only the surface layer of the coating is processed, while the said surface layer has a thickness of 10 nm to 1 μm, and at the second stage the coating is cured over its entire thickness. 2. The method according to claim 1, wherein, to irradiate the coating (32), UV-C radiation with a wavelength of 240 nm or more is introduced into its surface layer. 3. The method according to p. 1 or 2, and the irradiation is carried out in two stages so that at the first stage they emit a lower UV dose and create micro-folding, and at the second stage the film is completely cured, and a longer wavelength UV is used at both stages of curing radiation, such as a medium pressure UV emitter. 4. The method according to any one of paragraphs. 1-3, moreover, at one stage of irradiation, both micro-folding and deep curing are achieved, and moreover, the coating material is preferably made so that the absorption of UV radiation varies across the thickness of the coating agent layer. 5. The method according to any one of paragraphs. 1-4, and the irradiation of both the surface layer and the irradiation to cure the coating is carried out respectively by means of a mercury emitter medium pressure. 6. The method according to claim 5, both for irradiating the surface layer and for curing the coating (32), mainly the same medium pressure mercury emitter is used, and UV dose adjustment is carried out by adjusting the power of the medium pressure mercury emitter. 7. The method according to any one of paragraphs. 1-6, and the coating is carried out in such a way that get a coating film, which has in certain areas different layer thicknesses. 8. The method according to any one of paragraphs. 1-6, and the coating (32) is carried out only on parts of the base (3), so that at least one area of the base (3) is uncovered, and at least one other area of the base (3) is covered. 9. The method according to any one of paragraphs. 1-6, and the coating (32) is carried out over the entire area of the base (3), and the thickness of the layer in different zones may be different. 10. The method according to any one of paragraphs. 1-9, and the irradiation of the surface layer is carried out over the entire area. 11. The method according to any one of paragraphs. 1-9, and the irradiation of the surface layer is carried out only in at least one area so that the surface effects due to micro-folding are achieved in at least one area thus treated, while in at least one untreated area the surface is smooth, not micro-folded. 12. The method according to p. 11, and only local irradiation of the surface layer to obtain micro-folding in at least one area is carried out by means of a mask or template with which / to shade the emitter zones, or by scanning the surface of the coating with local resolution. 13. The method according to p. 12, wherein the scanning is carried out due to the fact that the surface of the line is scanned line by line, the line is divided into separate image points or pixels, and each line is assigned to one stroke of the scanning head. 14. The method according to any one of paragraphs. 1-13, with various surface effects occurring in different areas of the coating (32). 15. The method according to any one of paragraphs. 1-14, and the irradiation is carried out by means of UV radiation in an inert gas atmosphere, preferably nitrogen atmosphere. 16. The method of claim 15, wherein the residual oxygen content is less than 5000 ppm, preferably less than 1000 ppm, or particularly preferably less than 500 ppm. 17. The method according to any one of paragraphs. 1-16, and the application of the coating fluid is carried out by a printing method, for example intaglio printing, flexographic printing, silk screen printing, pad printing or inkjet printing, or by rolling, pouring, squeegee, pouring, for example curtain or slot loading, immersion, spraying and / or by centrifugation. 18. The method according to any one of paragraphs. 1-17, and the degree of gloss of the coating (32) at an viewing angle according to DIN EN ISO 2813 is in the areas where the surface layer is exposed to micro-folding, after curing the entire layer 0.1-80 GE, preferably 0.1-50 GE , very preferably 0.1-20 GE, and particularly preferably 0.1-10 GE. 19. A device (6) for curing fluids of coatings configured to cure with energy-intensive particle radiation, in particular UV radiation, curing is carried out in two stages, and the power introduced by the device into the coating (32) for curing it can be adjusted so that in the first stage only the surface layer of the coating is treated, and in the second stage, the coating is cured over the entire thickness, said surface layer having a thickness of 10 nm to 1 μm. 20. The device (6) according to claim 19, including a medium pressure mercury emitter. 21. The device (6) according to claim 19 or 20, the device (6) for curing the layer is configured to illuminate the surface layer only in the coating area (32) and curing the coating (32) over its entire area. 22. The device (6) according to any one of paragraphs. 19-21, and the device (6) includes information means for controlling the curing of the coating, in particular, so that the information means is configured to determine the power, dose and / or place of curing. 23. A device (1) for creating surface effects in at least one portion of a base (3) coated with a coating (32) configured to cure with energy-intensive particle radiation, in particular UV radiation, the device including: - mainly a device (301) for placement of the base, - means for transporting the base (3) between the individual working positions, - a device (4) for applying a coating fluid to a substrate (3), wherein the device (4) can be configured to apply a coating fluid throughout the surface area (31) of the substrate (3) or in only one portion thereof, - a device (6) for curing the coating, and curing takes place in two stages, and the power introduced by the device into the coating for curing can be configured to process only the surface layer of the coating in the first stage, and the surface layer has a thickness of 10 nm up to 1 μm, and in the second stage - curing of the coating throughout the thickness, - mainly a device (302) for extracting the base (3), and - mainly device (5) control the installation, moreover, the device (6) for curing the coating (32) is made predominantly in one or more paragraphs. 19-22. 24. The coating fluid, made with the possibility of curing by energy-intensive particle radiation, in particular UV radiation, in particular due to radical polymerization, and also accessible to the micro-folding process, moreover, micro-folding occurs due to irradiation of the surface layer of the applied coating, for example, by irradiation with UV With C-radiation with a wavelength of more than 240 nm, thus, at the first stage, only the surface coating layer is processed, while said surface layer has a thickness of 10 nm to 1 μm And the second stage coating is cured throughout its thickness. 25. The coating fluid of claim 24, having a composition of 100 parts of a liquid binder for 13 parts of a mixture of photoinitiators and / or crosslinking agents and / or activators. 26. The coating fluid of claim 24 or 25, containing photoinitiators that form radicals. 27. The coating fluid according to any one of paragraphs. 24-26, containing a tertiary amine, preferably H-methyldiethanolamine or amine-modified acrylate. 28. The coating fluid according to any one of paragraphs. 24-26, containing an acrylate-based binder. 29. Product (300) for use in the printing industry, and / or for aviation, and / or for water transport, including a base (3) and a coating (32) applied to it, wherein the coating (32) at least one area includes a micro-folding surface layer, said surface layer having a thickness of 10 nm to 1 μm. 30. Product (300) according to claim 29, wherein the base (3) includes paper, cardboard, laminated paper or laminated cardboard, polymer films, as well as corrugated cardboard substrates, or a polyolefin film, or a PET or acetate film. 31. The product (300) according to claim 29 or 30, wherein the degree of gloss in at least one area having micro-folding is preferably 0.1-50 GE, very preferably 0.1-20 GE, and particularly preferably 0.1- 10 GE, with viewing angle to DIN EN ISO 2813. 32. Product (300) according to any one of paragraphs. 29-31, having at least one zone with a first surface effect due to micro-folding, at least one other zone with a second surface effect due to micro-folding, and at least one zone without micro folding, and the thickness of the coating layer (32) between the individual zones is not more than than 10% differs from the specified layer thickness, which corresponds to the thickness of the coating in a non-folding state. 33. The product (300) according to any one of paragraphs. 29-32, manufactured, in particular, by the method according to any one of paragraphs. 1-18.

Images