EP0993876B1 - Process for applying a coloured decoration onto a substrate - Google Patents

Description

The invention relates to a method for applying a color decoration on a substrate using a carrier with so-called "Release" properties.

In particular, the following are considered as material for the substrates: Glass, metal, ceramic materials, plastics, wood, Wood materials, textiles and leather.

Carriers with "release" properties are known as such (cf. EP 0 573 676 A1). As a flat carrier with "release" properties certain papers are particularly considered or also plastic films that glisten on their surface or are prepared that applied under certain conditions Layers of paint or varnish in the manner of a "Peeling off" (like a decal) can be transferred to a substrate are. For the present invention come in particular as Carrier with "release" property plastic films, such as in particular Polyester films, which have a suitable release layer to achieve the "Release" (Abpell) property.

The aforementioned EP 0 573 676 A1 already describes the use a carrier with a "release" property for applying Color decor on a substrate. With this state of the art for this purpose, the color decor on a support "Release" property applied, then over that on the straps applied color decor applied a varnish, the varnish then partially networked and then under pressure and / or increased The temperature of the partially cross-linked paint together with the color decoration from the bearer transferred to the substrate to be ultimately decorated in such a way that the paint is under the color decor on the substrate. Finally there is a further crosslinking of the lacquer the substrate.

For the technique of color decoration in question comes here it depends on the substrate in a variety of applications to be primed in a suitable manner with a varnish.

The present invention aims to provide a method of application a color decor on a substrate of the aforementioned Kind so that a primer of the substrate with very good adhesive and masking effect is achieved. Farther the process is to deliver decorated substrates (objects), which show a very good visual impression of the decoration, in particular a deep effect of the coloring, good adhesion the applied layers of paint or varnish with each other and also a high scratch and abrasion resistance of the color decoration covering lacquer layer.

a) Ein Farbdekor wird auf einen flächigen Träger mit "Release"-Eigenschaft aufgebracht,

b) über das auf den Träger aufgebrachte Farbdekor wird ein Lack aufgetragen,

c) der aufgetragene Lack wird teilvernetzt,

d) der teilvernetzte Lack mitsamt dem Farbdekor wird vom Träger auf das Substrat so übertragen, daß der Lack unter dem Farbdekor auf dem Substrat aufliegt und der Träger vom Farbdekor entfernt wird,

e) über das auf das Substrat übertragene Farbdekor wird eine obere Lackschicht aufgetragen, und

f) die Lackschichten werden mittels Strahlung gehärtet.

According to a first variant of the invention, a method is provided with the following steps:

a) A color decor is applied to a flat support with "release" property,

b) a varnish is applied over the color decor applied to the support,

c) the applied lacquer is partially crosslinked,

d) the partially crosslinked lacquer together with the color decoration is transferred from the support to the substrate in such a way that the lacquer lies under the color decoration on the substrate and the support is removed from the color decoration,

e) an upper layer of lacquer is applied over the color decor transferred to the substrate, and

f) the lacquer layers are hardened by means of radiation.

a) Ein Farbdekor wird auf einen flächigen Träger mit "Release"-Eigenschaft aufgebracht,

b) über das auf den Träger aufgebrachte Farbdekor wird eine Kleberschicht aufgetragen,

c) der aufgetragene Kleber wird getrocknet oder zumindest teilgetrocknet,

d) das Farbdekor mit dem gehärteten oder teilgehärteten Kleber wird so auf das Substrat übertragen, daß der Kleber unter dem Farbdekor auf dem Substrat aufliegt und der Träger vom Farbdekor entfernt wird,

e) über das auf das Substrat übertragene Farbdekor wird eine obere Lackschicht aufgetragen, und

f) die obere Lackschicht wird gehärtet und dabei wird der Kleber durch Wärme aktiviert, um eine vollständige Verklebung mit dem Substrat zu erreichen.

According to a second variant of the invention, a method is provided with the following steps:

a) A color decor is applied to a flat support with "release" property,

b) an adhesive layer is applied over the color decor applied to the support,

c) the applied adhesive is dried or at least partially dried,

d) the color decor with the hardened or partially hardened adhesive is transferred to the substrate such that the adhesive lies under the color decor on the substrate and the carrier is removed from the color decor,

e) an upper layer of lacquer is applied over the color decor transferred to the substrate, and

f) the upper lacquer layer is hardened and the adhesive is activated by heat in order to achieve complete adhesion to the substrate.

According to the invention in all two variants of the invention above the top coat of paint during or after radiation curing heated by radiation curing with electron beam.

Furthermore, according to the invention in all two variants above of the invention, the heating of the upper lacquer layer with a Hot gas jet carried out at least in one direction has a dimension (width) that is small compared to the dimension the color decor and the lacquer layer, the lacquer or the Adhesive layer in this direction.

For the color decor are preferred in all variants of the invention diffusible disperse dyes used, i.e. the color decor has such disperse dyes.

preferably the hot gas jet is in the form of a hot gas knife passed over the top layer of paint, in such a way that the temperature of the hot gas jet and a relative movement between the hot gas jet and the substrate are controlled so that essentially only warms the top layer of paint effectively becomes.

Furthermore, in the first variant of the invention it is preferred that the paint is a primer paint.

The partial crosslinking of the lacquer according to step c) of the first variant the invention is preferably carried out with UV radiation.

It is preferably provided that the hot gas jet on a Temperature at which it causes or at least promotes, that dye of the color decoration in the one above it Lacquer layer diffuses. This makes a very particular achieved good aesthetic effect of the decorated product, in particular a certain depth effect of the coloring. The Dye molecules diffuse different distances, each by molecular weight, in the paint above, what the affects the visual impression of the decoration.

The adhesion of the layers to each other and also the mechanical Properties of the applied lacquer and dye layers can according to a further preferred embodiment the invention are promoted in that the hot gas jet the shape of a knife when hitting the top layer of lacquer and has a line over the top layer of lacquer becomes. In particular, this technique can be used to precisely target Temperature increase for a certain period of time up to one certain depth of the layers can be achieved without the underlying paint or adhesive layer to the same temperature is increased like the top layer of lacquer on the substrate. This allows the diffusion of the dye molecules in the desired Controlled way, namely especially in the over the layer of paint lying on the dye light, for which therefore in particular a transparent lacquer or at least largely transparent or white lacquer is provided.

In the colored decoration and painting of products are often the edge and edge areas of the product are critical. According to A preferred embodiment of the invention is quality the lacquered decoration especially in the edge area promoted in that the linear hot gas jet (in particular Hot air jet) is guided so that it affects the affected Edge or the edge of the substrate with the ones lying on it Edge covering paint and varnish layers detected, so z. B. with a right-angled edge on both surfaces equally acts.

Figur 1

schematisch einen Träger mit "Release"-Eigenschaft und darauf aufgebrachter Farbdekorschicht sowie daraufliegender Lackschicht;

Figur 2

ein zu dekorierendes Substrat mit daraufliegenden Lack-, Farb- und Lackschichten;

Figur 3

schematisch eine Abwandlung des Ausführungsbeispieles gemäß den Figuren 1 und 2, bei der ein Kleber statt einer Lackschicht verwendet wird; und

Exemplary embodiments of the invention are explained in more detail below with reference to the drawing. It shows:

Figure 1

schematically a carrier with a "release" property and a color decorative layer applied thereon and a lacquer layer thereon;

Figure 2

a substrate to be decorated with layers of lacquer, paint and lacquer on top;

Figure 3

schematically shows a modification of the embodiment according to Figures 1 and 2, in which an adhesive is used instead of a lacquer layer; and

Figure 1 shows a carrier 10 with "release" properties. At the The illustrated embodiment is a polyester film.

A color decor 12 is printed on the carrier 10, e.g. B. with Rotary printing or digital printing. The available ones Printing techniques as such are known to those skilled in the art.

A first lacquer layer 14 is applied to the color decor 12. In the exemplary embodiment, a lacquer is chosen which is used as the base lacquer is suitable for the substrate that is ultimately to be decorated, thus the surface structure of the substrate in the desired Way so that good adhesion of all applied Paint and color layers on the substrate is reached '. The paint layer can be transparent or colored. Furthermore, in particular the lacquer layer applied to the bottom of the substrate prefers a base color for the decor above his. If e.g. the decor should be walnut-like, the Basic color of one of the lacquer layers or both lacquer layers be brown. Furthermore, it can be provided that the lacquer layers, especially the lower layer of lacquer on the substrate, which promotes adhesion Has properties. The base coat of paint can also be used with regard to the application weight so that unevenness, Cracks, holes etc. in the substrate can be compensated. Furthermore, the base lacquer layer can have adhesive properties, in particular, the base lacquer layer as a whole can be trade a glue.

Acrylic lacquer, polyurethane lacquer, Polyester paint and the like. In particular water-soluble paints used, preferably no paints with Solvent.

The paint 14 applied to the color decor 12 is a so-called. Partially crosslinked. A "partial networking" means that the paint has not yet been completely crosslinked will, but only partially, so that later a complete one Networking is made possible. The networking of paints is that Known to those skilled in the art. Networking can e.g. B. with increased Temperatures, especially using infrared radiators be performed. Networking is promoted by so-called hardeners. In the illustrated embodiment, the achievement a subsequent good primer of the to be decorated Substrate and good adhesion of the layers the partial crosslinking of the first lacquer layer 14 with UV radiation 16.

After the partial crosslinking, the system prepared in this way becomes a carrier 10, color decor layer 12 lying thereon and lying thereon partially cross-linked first lacquer layer 14 on a to be decorated Substrate 18 laid around the lacquer layer 14 and the color decor 12 to transfer to the substrate 18. The paint layer is there 14 directly below on the substrate 18, as shown in FIG. 2 is. The transmission takes place with the one explained at the beginning "Release" technique. The first lacquer layer 14 serves as a primer of the substrate 18.

Via the lacquer and dye layers 14, 12 thus transferred a second lacquer layer 20 is applied. For the second Paint layer 20 can use the types of paint mentioned above find, especially a transparent lacquer or a (light) white colored lacquer.

The top coat layer 20 is chosen to be relatively thick, in particular in the range from 40 to 120 μm, particularly preferably in the range from 60 to 100 µm. These strengths of the lacquer layer 20 are important for the diffusion of the dye molecules described below.

After the second lacquer layer 20 has been applied, electron beam curing takes place. In Figure 2, the electron beam with the Reference number 22 is indicated schematically. A paint hardening with As such, electron beam (ESH) is familiar to the person skilled in the art.

The paint curing is carried out so that essentially both Lacquer layers 14, 20 are fully hardened.

a) Zumindest einer der genannten Lacke kann thermoplastischer Natur sein. In diesem Fall wird er nicht mit Strahlung teilvernetzt, sondern thermisch getrocknet oder angetrocknet, bevor die Übertragung auf das zu dekorierende Substrat erfolgt. Im Falle einer thermischen Trocknung oder Antrocknung "schmilzt" der Lack (ggf. leicht) an und beim Aufpressen und Erwärmen verbindet er sich mit dem Substrat bzw. haftet gut auf dem Substrat. Bei einem thermisch trocknenden (härtenden) Lack ist in der Regel eine Nachhärtung mit Strahlung nicht sehr effektiv. Als solche Lacke kommen insbesondere in Betracht thermoplastische Bindemittelsysteme, also z.B. Acryllacke, PU-Lacke, Polyesterlacke etc., und zwar in wäßriger, lösungsmittelhaltiger Form oder in reiner Form. Solche Lacke können auch sogenannte Härter enthalten.

b) Andererseits kann, wie oben anhand des Ausführungsbeispieles näher beschrieben, der Lack strahlenvernetzbar sein. In diesem Falle wird er mit UV teilvernetzt und nach dem Aufbringen auf das Substrat wieder mit Strahlung weitervernetzt, vorzugsweise mit Elektronenstrahl. Der Lack kann in diesem Falle gemäß einem radikalischen oder einem kationischen Mechanismus härten und es können die jeweils bekannten Bindemittel eingesetzt werden.

c) Weiterhin kann der Lack im eigentlichen Sinn ein Kleber sein. In Betracht kommen sowohl thermisch härtende Kleber oder strahlungshärtende Kleber. Im ersten Fall erfolgt die Verarbeitung wie vorstehend unter a) angegeben ist. Im zweiten Fall (strahlenhärtend) kann die oben beschriebene Teilvernetzung bzw. die Vollvernetzung mit Strahlung durchgeführt werden, wobei die klebenden Eigenschaften bei der Teilvernetzung erhalten bleiben. Die Vollvernetzung kann mit ESH durchgeführt werden.

The following generally applies to the paints used:

a) At least one of the paints mentioned can be thermoplastic in nature. In this case, it is not partially crosslinked with radiation, but is thermally dried or dried before it is transferred to the substrate to be decorated. In the case of thermal drying or drying, the lacquer "melts" (possibly slightly) and when pressed and heated, it bonds to the substrate or adheres well to the substrate. In the case of a thermally drying (hardening) lacquer, post-curing with radiation is generally not very effective. Such lacquers are in particular thermoplastic binder systems, for example acrylic lacquers, PU lacquers, polyester lacquers, etc., in aqueous, solvent-containing form or in pure form. Such paints can also contain so-called hardeners.

b) On the other hand, as described in more detail above using the exemplary embodiment, the lacquer can be crosslinkable by radiation. In this case, it is partially crosslinked with UV and, after being applied to the substrate, crosslinked again with radiation, preferably with an electron beam. In this case, the lacquer can harden according to a radical or a cationic mechanism and the known binders can be used.

c) Furthermore, the varnish can actually be an adhesive. Both thermosetting adhesives or radiation-curing adhesives can be considered. In the first case, processing is carried out as indicated under a) above. In the second case (radiation-curing), the above-described partial crosslinking or the full crosslinking can be carried out with radiation, the adhesive properties being retained during the partial crosslinking. Full networking can be carried out with ESH.

In the cases b) and c) above, the paints can also in aqueous, solvent-based or in 100% form the paint can be applied.

According to the ESH, a so-called "Hot air knife" used. It is a Hot air jet coming from a nozzle 24 directly onto the top one Lacquer layer 20 is applied. For this purpose, hot air 26 flows through The nozzle 24. In the illustrated embodiment, the Hot air jet "knife-shaped", d. H. it has the shape of a line, which is perpendicular to the plane of the drawing and is preferred across the entire width of the paint and dye layers as well of the substrate 18 extends. Such a "hot air knife" can corresponding to arrow 28 relative to substrate 18 with those lying thereon Paint and dye layers are moved.

Such a "hot air knife" 24, 26 can be used here Process can be used in various ways. First the hot air knife can serve to transfer the Color decorations 12 with the partially crosslinked lacquer layer 14 from the carrier 10 onto the substrate 18 (i.e. the transition from FIG. 1 to FIG 2) to promote. The hot air knife can first of all be used in this process, the support 10 lying on top with the underlying ones Paint and varnish layers 12, 14 against the substrate 18 be pressed. Strokes the hot air knife over the carrier 10, there is a full-area, even system and the partially networked Lacquer is pressed against the substrate 10 and its adhesive effect promoted on the substrate. This makes peeling easier ("Peeling") of the carrier 10.

Particularly beneficial for the decoration technology used here is the use of the hot air knife 24, 26 after the electron beam hardening the layers of paint 14, 20. With the hot air knife can the temperature of the upper layer of lacquer 20 and the underlying Dye layer 12 can be increased briefly in such a way that a clear temperature gradient from top to bottom is given, d. H. the top lacquer layer 20 is hotter than that bottom paint layer 14. This causes the dye molecules diffuse from the color decor layer 12 into the upper lacquer layer 20. In the case of diffusible disperse dyes, that depends Color and thus the diffusion rate of the dye in usually depends on the molecular weight. Roughly said z. B. yellow Colors have a typical molecular weight of 200 to 300, red of 250 to 350, blue from 300 to 400 and black from 350 to 500. This has the consequence that in the thermal diffusion described above the light dyes, such as yellow, continue to diffuse than the darker dyes, such as B. blue or black. hereby becomes a 3-dimensional depth effect of the color decoration reached. The above strengths for the top lacquer layer 20 enable this depth effect due to different diffusion distances of the individual dye molecules.

The hot air knife mentioned is particularly suitable for this process, because it's a short-term very targeted temperature increase with the temperature gradient mentioned. The temperature the hot air 26 and the speed of the relative movement between nozzle 24 and substrate 18 with those lying thereon Lacquer and dye layers are adjusted so that the above explained effect is achieved. The locally limited Hot air knife enables a brief temperature increase with temperature gradients without immediately being complete even distribution of heating occurs, d. H. without a uniform temperature distribution in the paint and Dye layers sets before the targeted described above Diffusion of the dye molecules into the top layer of lacquer 20 is essentially achieved.

As said, the nozzle 24 is shaped so that the hot air jet in the form of an elongated line on the top layer of lacquer 20 hits. This enables in particular a good quality decoration of the substrate 18 in the particularly critical edge area 30. The line-shaped hot air jet (the "Hot air knife") guided obliquely over the edge area 30, see above that a uniform pressure and temperature influence on both edge surfaces is given by the gas jet. It can too several hot air knives at different angles at the same time be used.

Figure 3 shows a modification of the embodiment described above of the invention, being instead of the first a layer of glue now lying on the substrate 14a is used. It can e.g. B. Glue on water or solvent base can be used. Be considered e.g. Polyurethane glue or acrylate-based glue.

The procedure is otherwise analogous to that described above with reference to FIG Figures 1 and 2 described method, d. H. on a carrier (not shown in Figure 3) with "Release" property is initially applied a color decor of the type mentioned and above the adhesive layer 14a. The adhesive layer 14a is then dried or at least partially dried and by means of The "color" decor 12 and the one below it then become the "release" technique Adhesive layer 14a on the substrate 13 to be decorated transferred, with the adhesive layer 14a on the bottom The substrate lies, as shown in Figure 3. Then one can Lacquer layer 20a are applied over the color decor 12. At the Hardening of the lacquer layer can also activate the adhesive at the same time be, e.g. B. by heat. This is in adhesive technology known as such.

Claims (9)

1. A method of applying a coloured decoration (12) to a substrate (18), comprising the following steps:

   a) a coloured decoration (12) is applied to a sheetlike support (10) having a release characteristic;

   b) a coating material (14) is applied over the coloured decoration (12) applied to the support (10);

   c) the applied coating material (14) is partially crosslinked;

   d) the partially crosslinked coating material (14) together with the coloured decoration (12) is transferred from the support (10) to the substrate (18) in such a way that the coating material (14) lies on the substrate (18) beneath the coloured decoration (12), and the support (10) is removed from the coloured decoration (12);

   e) an upper coating film (20) is applied over the coloured decoration (12) transferred to the substrate (18), and

   f) the coating material (14) and the coating film (20) are cured completely,
   characterised in that

   g) for curing of the upper coating film (20) a curing with electron beam (22) is carried out and

   h) heating of the upper coating film (20) is performed with a hot gas jet (26) which, at least in one direction, has a dimension (width) that is small in this direction as compared to the dimension of the coloured decoration (12) and the upper coating film (20).
2. The method of applying a coloured decoration (12) to a substrate (18), comprising the following steps:

   a) a coloured decoration (12) is applied to a sheetlike support (10) having a release characteristic;

   b) an adhesive film (14a) is applied over the coloured decoration (12) applied to the support (10);

   c) the applied adhesive film (14a) is dried or at least partially dried;

   d) the coloured decoration (12) with the cured or partially cured adhesive (14a) is transferred from the support (10) to the substrate (18) in such a way that the adhesive film (14a) lies on the substrate (18) beneath the coloured decoration (12), and the support (10) is removed from the coloured decoration (12);

   e) an upper coating film (20a) is applied over the coloured decoration (12) transferred to the substrate (18), and

   f) the upper coating film (20a) is cured and the adhesive film (14a) is activated so as to achieve complete bonding to the substrate (18),
   characterised in that

   g) for curing of the upper coating film (20) a curing with electron beam (22) is carried out and

   h) heating of the upper coating film (20) is performed with a hot gas jet (26) which, at least in one direction, has a dimension (width) that is small in this direction as compared to the dimension of the coloured decoration (12) and the upper coating film (20).
3. The method according to one of Claims 1 or 2, characterized in that
   a relative movement (28) is carried out between the hot gas jet (26) and the substrate (18).
4. The method according to Claim 1, characterized in that
   the coating material (14) is a primer coating material.
5. The method according to Claim 1, characterized in that
   the partial crosslinking of step c) is carried out with UV radiation.
6. The method according to Claim 1 or 2, characterized in that
   the hot gas jet (26) is heated to a temperature at which is causes, or at least assists, the dye of the coloured decoration (12) to diffuse into the upper coating film (20, 20a).
7. The method according to Claim 6, characterized in that
   the temperature of the hot gas jet (24) and a relative movement (28) between the hot gas jet (26) and the substrate (18) are controlled in such a way that essentially only the upper coating film (20) is effectively heated.
8. The method according to Claim 7, characterized in that
   the gas jet (26) contacts at least one edge of the substrate (18) with the overlying dye and coating films (12, 14, 20, 20a) which cover the edge.
9. The method according to Claim 8, characterized in that
   when it impinges on the topmost coating film (20) the gas jet has the form of a knife and is guided linearly over the upper coating film.

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