DE4421559C2 - Process for producing a coating having a structure on a substrate and coating - Google Patents

Description

The present invention relates to a method of manufacture len a coating that has a structure, especially texture or grain, has, on a substrate and by means of Coatings produced according to the method of the invention.

Coating substrates, especially wood and wood similar substrates, with those that can be crosslinked by electron beams Varnishing leads to materials with good surface properties in terms of hardness and resistance to chemical like mechanical loads. Will that be through electron beams crosslinkable paints with pigments or dyes mixed used, can also be excellent quality pro products with colored surfaces can be obtained.

It is often the case with wood-like materials wishes also a grain in the form of a wood structure on the Apply surface to make the material more natural seem to make. Also, through additional structuring the material surface in general has a number of advantages harmful effects, especially in connection with a use colored paints can be achieved.

Due to the hardness of a coating made by electron beam However, crosslinkable lacquers are an additional structure Ren the surface difficult and leads especially at more demanding structures not satisfactory results nits.  

EP 0210620 A2 describes a method for producing a Described textured lacquer layer film, in which a hardenable lacquer layer by electromagnetic radiation or partially hardened or dried by exposure to heat, the partially hardened or dried paint layer with the Provide texturing and then the texturing provided paint layer alternatively by electromagnetic Radiation or heat is completely hardened. For curing under the influence of heat will be temperatures of stated at least 50 ° C, preferably 70 to 80 ° C.

JP 3-174279 A2 describes a method for producing a coated and provided with a structure under Described using a radiation-crosslinkable lacquer, whereby the lacquer layer exclusively by ionizing Radiation is cured in two process steps.

JP 2-284676 A2 describes a method for producing a coated and provided with a structure under Described using a radiation-crosslinkable lacquer, the lacquer layer similar to that in JP 3-174279 A2 is cured exclusively by ionizing radiation.

JP 59-132975 A2 discloses a method of manufacturing embossed decorative materials that are embossed under Heat exposure ("hot-press embossing"), for example comprises a topcoat layer fully crosslinked by radiation. In the Heating described in connection with the embossing process is evident to soften the fully cross-linked Surface to in an immediately following Process step using an embossing roller into the pattern To emboss the surface.

The invention has for its object a method by which was coated with radiation-crosslinkable paints Substrates can be produced, which on their Surface are provided with a structure, as well as by to provide coatings obtained by this process, the coatings being characterized by increased hardness.

This object is achieved by those described in the claims Process and coatings solved.

The invention comprises a method for producing a Coating that has a structure, especially a texture or Grain, has, on a substrate with the features according to Claim 1.

The substrate can be any, preferably plate-shaped Mige substrate, which with a radiation-crosslinkable Lacquer is coatable. The term "substrate" also includes here Materials with a primer and / or a decor are provided. The primer can act as an adhesion promoter for the radiation-crosslinkable lacquer and / or the decor or for Serve surface sealing or preparation.

As possibly only after priming or surface coating action can be coated with a radiation-crosslinkable lacquer For example, substrates can be plastics, especially ther plastic materials, metal, wood and wood-like material fe, such as wood fiber or gypsum boards, etc., papers, glass as well ceramic materials are called.

As a substrate for the method according to claim 2, which provides for additional application of a primer according to the invention in particular a wood, a wood comprising or a wood-like substrate is provided. Preferably be plate-shaped substrates used. examples for this are Wood fiber boards, wood cement boards, wood polypropylene boards, Plasterboard u. Ä. and papers.  

The primer of the substrate serves to seal the pores, to reduce the need for radiation-crosslinkable lacquer as little as to keep possible. For this purpose, the expert in this together Menhang used known compositions as such.

The lacquer layer preferably comprises a radiation-crosslinkable one Composition known in the art. For Systems to be used include known radiation-curing acrylic prepolymers, such as polyurethane, polyester, poly ether, epoxy or full acrylates or mixtures thereof. This can also with known low viscosity Re mixed active thinners.  

Furthermore, according to a cationic curing mechanism wettable coating systems are used, such as Ep oxides or vinyl ethers, mixtures thereof or mixtures of Epoxides and / or vinyl ethers with the aforementioned acrylic ten.

In one embodiment of the method according to the invention the above-mentioned lacquer which can be crosslinked by blasting one or more photoinitiators known as such offset are used, which have a cross-linking ability Convey UV rays. All are used here known photoinitiators and photoinitiator mixtures, given if with known coinitiators and sensitizers mixed goals.

Is only a partial crosslinking of the radiation crosslinkable If the lacquer layer is aimed at using UV radiation, the or the photoinitiators are added in an amount that is less than the amount of photoinitiator that is Lamp power and a predetermined path or substrate speed is necessary to create a full network len. The procedural para required in this context meters are known to those skilled in the art as such. Typically be carries the amount of photoinitiator or photoinitiator mixture, optionally together with so-called coinitiators and sen sibilizers, 0.1 to 3% by weight, preferably 0.2 to 1.5% by weight, each based on the overall formulation of the paint.

In a further embodiment of the method according to the invention rens can crosslink the above, by radiation paint with proportions of thermally crosslinkable resins or Varnish systems that further solidify the radiation enable cross-linked coating under the influence of heat, ge mixes can be used.  

The radiation-crosslinkable lacquer can also contain inorganic, organic or metallic fillers, matting agents, rheological additives or waxes. To certain own To achieve shaft profiles, additives, additives, such as leveling agents, lubricants, deaerators, defoamers, adhesive improvers, dispersing agents, wetting agents, antiab setting agents, antistatic agents, stabilizers, light stabilizers, Corrosion protection agents and other substances known to those skilled in the art Fe, individually or in a mixture.

Furthermore, the radiation-crosslinkable lacquer can have one or who added several thermally acting crosslinker components the. The radiation-crosslinkable lacquer comprises prepolymers which contain reactive groups with the thermal crosslinker Component react under the influence of temperature, so an over the radiation-induced networking goes beyond further ver system.

The radiation-crosslinkable lacquer can be known as such in one processes such as spraying, rolling, casting or an order in the immersion process.

The partial crosslinking of the lacquer layer from the radiation crosslinkable Ren composition can by means of electron beams and / or UV rays occur. The term "partially networked" means that the paint has not yet been completely crosslinked is, but only partially, so that later a complete networking is possible. The crosslinking of paints by means of UV and electron beams are known to those skilled in the art as such knows.

Is the partial crosslinking of the lacquer layer by means of electrons a radiation dose is usually used for this purpose which is less than the dose required for complete Networking is necessary. Typically, strah come for this loses of 0.5 to 10 kGy (= 0.05 to 1 Mrad), preferably 1 up to 5 kGy (= 0.1 to 0.5 Mrad).  

The extent of crosslinking using UV rays is generally mean with given UV lamp power and given Web or substrate speed over the amount of Photoini tiator (s) regulated which the radiation-crosslinkable lacquer is added.

Parts of the radiation-crosslinkable lacquer layer were thermal crosslinkable resins or coating systems added, the partial ver nets can also be caused by heat. The necessary for this The amount of energy and duration of treatment results for the Specialist from the use of the ther used in individual cases mixable systems based on their known properties ten.

In a preferred embodiment, the lacquer layer can that in European Patent Application No. 92 108 427.3 (Ver publication number 0570607) disclosed methods of order lacquer (and paint) on a substrate by means of a carrier with "release" properties (see European patent application No. 92 108 426.5; Publication number 0573676) will.

For this, the paint layer, in this case from a jet Lung-crosslinkable composition, previously on the carrier with "release" properties applied and on this by means of Radiation partially cross-linked. The partially crosslinked lacquer layer is then under pressure and / or elevated temperature from the carrier to the Transfer substrate. Preferably, the transfer of the varnish layer can be carried out by means of a calender, in particular which has at least one roller made of elastic material. Because here the lacquer layer is already in a partially cross-linked state the substrate is applied, the partial crosslinking step omitted on the substrate.

Applying the structure, texture or grain to the upper surface of the partially crosslinked lacquer layer can be used using only slight pressure using an embossing cylinder or plate or a structured or embossed paper or one  appropriate film in a conventional manner. The Embossing of the paper or the foil can be done by a embossed lacquer or plastic layer can be achieved.

It can be particularly advantageous here to use the partially cross-linked Varnish before applying the structure, texture or grain warm up to make it more elastic and thus the embossing of the Simplify pattern. The heating can, for example, with infrared rays or hot air.

In a further embodiment, the invention comprises in particular a method with the features according to claim 3.

The decor can be done for example by means of offset, rota tion, gravure, flexo or screen printing processes as images, samples, Individual color or motif can be printed directly on the substrate. However, the decor can also be made of a carrier material in itself known manner in the form of a "decal" or by means of a Transfer printing process can be transferred to the substrate.

The use of decorations based on sublimable dispersions dyes are special in the context of the present invention prefers. In particular, pressure is used for this application used inks, which in addition to the sublimable dispersions conventional dyes binders and optionally Include oxidation additives.  

In a particular embodiment of the Ver After painting, the paint layer and the decor can be done together in the EP 0570607 A1 disclosed method for applying Paint and paint on a substrate using a carrier with "re lease "properties (cf. EP 0573676 A1). The method already briefly described above will go away going modified that on the partially crosslinked paint layer Decor is applied and then the partially cross-linked lacquer together the decor under pressure and / or elevated temperature from the wearer is transferred to the substrate, so that the decor directly optionally primed substrate rests.

It is for better adhesion of the decor to the primer advantageous to the primed and decorated substrate before Application of the radiation-crosslinkable lacquer layer, for example wise to heat with infrared rays or hot air. This is particularly advantageous if the decor is without action heat has been applied to the primed substrate is.

In a modified form of the Ver The decor can also be applied to the radiation-crosslinkable lacquer layer can be applied. To do this, the paint layer is first by means of radiation, in particular UV and / or electron beam lung, or thermally partially cross-linked and then the decor after applied one of the methods described above. A for the "development" of the color effect when using sub Limable disperse dyes may require heating then take place before or after the crosslinking of the lacquer layer.

The full crosslinking of the radiation-crosslinkable lacquer layer follows preferably by means of electron beams, but can also with UV rays. Through full networking, the Lacquer layer hardened, the one applied to the surface Structure is fixed without change.  

For full crosslinking using electron beams Radiation cans are used to fully network the Paint system. Typically, radiation doses are used for this from 10 to 100 kGy (= 1 to 10 Mrad), preferably 10 to 50 kGy (= 1 to 5 Mrad) used.

According to the invention, the method according to the invention additionally comprises Lich the process step, the varnish after full crosslinking to warm in addition. On the one hand, this has a further effect extensive networking and thus hardening of the lacquer layer, in particular their surface; on the other hand, the heating serves to "Develop" the color of the decor, if it is sublimable Disperse dyes includes by these dyes by the Sublimate heat and into the overlying paint layer as well as in the underlying primed substrate immigrate layer. As a result, the color of the decor gains Intensity, brilliance and depth effect.

The heating is preferably carried out by means of infrared rays, can, for example, also by means of convection or hot air can be made.

The temperature of the substrate as it heats up surface is critical. Too high a temperature leads to fine cracks in the coating, whereas one to low temperature not to the maximum possible additional hardness tung leads. The preferred temperature range is between 170 and 220 ° C depending on the paint used.

The heating of the radiation-crosslinked lacquer is done before depending on the over the entire surface of the Lacks measured output temperature regulated. This can be done at for example the surface of the radiation cross-linked substrate can be scanned using a line scanner to determine the tempe temperature of the substrate surface over its entire surface grasp, and the performance of the infrared emitter accordingly  being controlled. Alternatively, infrared cameras (Thermovi sions camera) with which locally resolved Temperature distributions are measurable. An infrared camera enables light the measurement of the individual temperatures in a matrix well-divided field.

Additionally or alternatively to the application of a decor The method according to the invention can include radiation crosslinkable lacquer with a colorant, which for example soluble dyes as well as organic or inorganic pig can include elements as coloring substances, mixed to use.

According to the invention, sublimable dispersions are also for this purpose dyes preferred as coloring substances. In a ver Use of these dyes leads to the final heating a "development" of the color in the lacquer layer. Through the heat-related sublimation and subsequent migration becomes the Ver dye evenly throughout the entire paint layer divides what leads to a particularly brilliant and deep color leads to pressure on the substrate.

The coating with radiation-crosslinkable lacquer can also be used in two or more layers are applied. Becomes a colored Desired substrate surface, for example, the sub strat or the layer of colored layer directly on the decor Lacquer can be provided, whereas the one on top Layer of undyed clear coat is applied. This under supports the depth effect of the color.

Additionally or alternatively, you can also use a colorant mixed primers can be used. Preferred dye with tel include one or more sub Limitable disperse dyes as coloring substances.

In addition, by combining a decor with a colored paint and / or a colored primer special Effects are achieved, for example when using metal lish-looking decors or primers.  

The present invention further includes an embodiment The method described above in which the application of the decor and the application of the texture, structure or mase Positioning the same on an upper surface of the substrate is coordinated. In this way For example, wood-like panels can be obtained the one in which the pattern of the wood imitating decor and the wood-like grain of the surface match.  

The invention also includes those of the invention Processes obtained coatings.

The methods according to the invention are described in the following Drawing explained in more detail by way of example.

Fig. 1 shows schematically a procedure according to the invention in which a plate-shaped substrate 10 is transported from a conveyor belt 12 from one processing station to the next.

First, the substrate 10 is fed to coating rollers 20 , which apply a primer to the substrate 10 . As a result, the primed substrate 10 passes through a UV channel 22 , in which the primer is partially crosslinked by means of UV rays.

The next step is to apply the decor to the partially cross-linked primer. For this purpose, a coated with a decor carrier 24 with "release" properties is used, which is unwound from a carrier unwinding roller 27 and is taken up again after transfer of the core from a carrier winding roller 26 .

The decorated with the carrier 24 is from the Trägerabwik kelrolle 27 fed via a roller 28 to a calender 30 . In particular, the calender 30 has at least one rubberized and optionally heatable roller, not shown here.

The decor is arranged on that side of the carrier 24 which faces the substrate 10 , which is likewise guided through the calender 30 . The calender 30 generates the required pressure and also the temperatures desired for the transfer at the contact point between the decor-coated carrier 24 and the substrate 10 . This is known as such in calender technology.

The carrier 24 freed from the decor is fed to the carrier take-up roll 26 via a further roller 28 and is taken up by the latter.

The primed and decorated substrate 10 is then fed to coating rollers 20 , which apply a UV and electron beam crosslinkable topcoat to the substrate 10 , and then passes through a further UV channel 22 in which the topcoat is partially crosslinked by means of UV rays becomes.

In the next step, a roller with a surface 32 structured according to a desired embossed pattern is guided over the surface of the partially crosslinked topcoat, as a result of which the topcoat surface is embossed.

In a subsequent radiation device with electron beam source 34 , the top coat provided with the embossing is fully crosslinked on the substrate 10 and further hardened in an infrared channel 36 to be traversed by additional crosslinking.

In this way you get a substrate with an extraordinarily hard and durable, decorated and structured coating. A further colored design of the surface is possible within the scope of this process sequence if the primer applied with the first pair of rollers 20 and / or the top coat applied with the second pair of rollers 20 are colored.

Claims (22)

1. A method for producing a coating, which has a structure, in particular texture or grain, on a substrate, comprising

• 1. - painting the substrate with a radiation-crosslinkable paint,
• 2. - a partial crosslinking of the lacquer,
• 3. - applying the structure to the partially cross-linked lacquer and
• 4. a full crosslinking of the lacquer by means of radiation,

characterized in that the lacquer is additionally heated by means of radiation after full crosslinking. 2. The method according to claim 1, characterized in that one with a primer provided substrate is used. 3. The method according to claim 2, characterized in that in addition to the primer Decor has been applied. 4. The method according to any one of claims 1 to 3, characterized in that the partial crosslinking by means of blasting, in particular by means of electron beams and / or UV rays, and fully crosslinked using electron beams becomes. 5. The method according to any one of claims 1 to 4, characterized in that the paint when heated to a Temperature between 170 and 220 ° C is heated.   6. The method according to any one of claims 1 to 5, characterized in that the heating of the lacquer by means of Infrared rays occur. 7. The method according to any one of claims 1 to 6, characterized in that the substrate is a wood, a wood comprehensive or a wood-like substrate. 8. The method according to any one of claims 3 to 7, characterized in that the decor one or more sublimable disperse dye (s) as colorant Contains substance (s). 9. The method according to any one of claims 3 to 7, characterized in that the decor using a Color carrier by means of a transfer printing process on the the substrate provided with the primer is applied. 10. The method according to any one of claims 2 to 9, characterized in that the primer with a Colorant is used mixed. 11. The method according to any one of claims 1 to 10, characterized in that the radiation-crosslinkable lacquer with mixed with a colorant. 12. The method according to any one of claims 10 or 11, characterized in that the colorant one or more sublimable disperse dye (s). 13. The method according to any one of claims 1 to 12, characterized in that the structure corresponds to that with the partially cross-linked lacquer coated substrate by means of an embossing cylinder or sheet is applied.   14. The method according to any one of claims 1 to 12, characterized in that the structure corresponds to that with the partially cross-linked lacquer coated substrate by means of a structure turured or embossed paper or film substrate is brought. 15. The method according to any one of claims 1 to 14, characterized in that the partially crosslinked paint before Applying the structure is heated. 16. The method according to claim 15, characterized in that the heating of the partially cross-linked Lacquers before applying the structure using infrared rays he follows. 17. The method according to any one of claims 1 to 16, characterized in that the heating of the fully cross-linked Varnishes depending on one over a surface of the varnish measured output temperature is regulated. 18. The method according to any one of claims 3 to 17, characterized in that the application of the decor and the Applying the structure in terms of positioning the same coordinates on a surface of the substrate he follows. 19. The method according to any one of claims 1 to 18, characterized in that on the radiation crosslinkable Paint layer before the paint is fully cross-linked using radiation a decor is applied. 20. The method according to claim 19, characterized in that the decor one or more sublimable dispersion (s) dye (s) as a coloring substance (s) comprises.   21. The method according to claim 20, characterized in that the lacquer layer provided with the decor before fully crosslinking the paint is heated. 22. Coating that has a structure, especially texture or Grain, has, on a substrate made by a Method according to one of claims 1 to 18.