DE102016003924A1 - Process for the dyeing of wooden moldings for vehicles and vehicles with such a wood trim - Google Patents

Abstract

The invention relates to a method for dyeing wood trim parts for vehicles with the following steps: application of a solvent ink to a visible surface of a wood trim part, and application of a water-based ink at least partially to the solvent ink.

Description

The invention relates to a method for dyeing wood trim parts for vehicles and a vehicle with a wood trim part.

From the German patent application DE 10 2014 011 138 A1 It is known to pretreat a wood trim for a motor vehicle bleach-free by the wood is thermally and / or electromagnetically aged. Thereafter, a primer by means of a paint or primer, wherein an ink application is carried out by means of a printing process. However, this method does not ensure a natural appearance of the wood trim part, and there is also a lack of desired high precision of the print and because of the instantaneous curing of the ink drops on the possibility of a color gradient for the formation of mixed colors.

The invention has for its object to provide a method for dyeing wood trim for vehicles and a vehicle with such a wood trim, said disadvantages do not occur.

The object is achieved by providing the subject matters of the independent claims. Advantageous embodiments emerge from the subclaims.

The object is achieved in particular by providing a method for coloring wood trim parts for vehicles, which comprises the following steps: A solvent ink is applied flatly to a visible surface of a wood trim part, and a water-based ink is applied at least partially to the solvent ink. The process makes it possible to reliably create a dyed wood trim with a natural look, which is also easy to form. These advantages are achieved in particular by applying a water-based ink to a surface-applied solvent ink. The specific properties of the various ink systems are exploited, the solvent ink having its strength in a high color intensity, but it is more difficult to handle in terms of precision, and the water-based ink has its strength in precision, but in the setting of color reproduction is more demanding. The two ink systems are combined for optimized decoration reproduction in an advantageous manner, wherein the solvent ink is used in particular for priming, in which case a regional, in particular local order, in particular a pattern is generated with the water-based ink.

An advantage of the method proposed here is in particular that the wood trim part - especially since there is no purely superficial paint application - gets a natural look, the grain is clearly visible. Due to the solvent ink, the color impression is provided in high intensity, and the water-based ink ensures the high precision of the coloring. By combining the inks, mixed colors can also form through the course.

As a wood trim part a veneer is dyed. It is possible that the veneer is arranged on a carrier, in particular laminated to the carrier, wherein the carrier wood or plastic, or may consist of wood or plastic. Other materials for the wearer are possible. It is possible that a laminating fleece is arranged between the carrier and the veneer.

By a solvent ink is meant a solvent-based ink wherein the solvent is not water. The solvent ink therefore particularly preferably has a nonaqueous, optionally hydrophobic solvent. In contrast, a water-based ink is understood to mean an ink which has, as solvent, water or an aqueous system, in particular an aqueous solution, in particular an aqueous solvent.

Under a visible surface of the wood trim part is understood a surface that is intended, when using the wood trim part, in particular in the interior of a vehicle, facing a viewer.

Preferably, the wood trim is primed in the area of the visible surface with the solvent ink. The visible surface is preferably printed with the water-based ink.

In this case, a direct printing method and / or a digital printing method can preferably be used, wherein a transfer of a predetermined pattern from a data processing device, in particular a computer, to an associated printing device is possible. It is possible that the wood trim is moved relative to an ink source for printing. It is also possible that the ink source is moved relative to the Holzzierteil. A combination of such relative movements is conceivable. Preferably, at least one of the inks is applied to the viewing surface by an ink jet. This can be done by a so-called ink-jet printing machine, which can be operated for example in continuous ink-jet mode or in a drop-on-demand mode. It is also possible to apply at least one of the inks by sublimation on the wood trim part.

It is possible for a decor carrier, for example a film, or a bonding agent to be arranged on the water-based ink. Optionally, a cover and / or protective lacquer can be arranged on the water-based ink or on the decor carrier or adhesion promoter, wherein the topcoat and / or protective lacquer can in particular comprise polyurethane or polymethylmethacrylate.

It is preferably provided that a white solvent ink is applied flat on the visible surface, whereby the visible surface is primed white with the solvent ink. Preferably, a colored water-based ink is at least partially applied to the solvent ink, wherein the wood trim part can be printed in the region of the visible surface with the colored water-based ink. It is possible that more than one water-based ink is used, in particular, different colors may be used, so that multi-color printing with a plurality of water-based inks can be realized.

It is also preferably possible that the wood trim part is back-injected, in particular after the application of the water-based ink. This can serve in particular to increase the stability of the wood trim. In particular, the back-molding can take place after a forming step, which preferably takes place after the application of the water-based ink.

The color formation by the printing in particular with the water-based ink is preferably such that small ink droplets deposit on the surface, the specific viscosity of the water-based ink and the surface properties of the visible surface influencing the flow behavior of the ink droplets. Due to the small size of the pigments of the water-based ink, they can reach even the smallest structures on the visible surface. Due to the specific interaction with the wood, the ink droplets settle on the wood structures. The solvent strikes away or dries, leaving behind the pigments of the ink - and in particular also binders which embed the pigments or, as a non-visible material, ensure the adhesion of the pigments.

According to one embodiment of the invention, it is provided that the water-based ink is applied locally, in particular in the form of a pattern. Thus, it is preferably provided that by means of the water-based ink, a printing of the wood trim part in the region of the visible surface, in particular with a pattern, preferably a geometric pattern, or with an image, icon, text or the like. However, it is also possible a full-surface application of water-based ink.

According to one embodiment of the invention it is provided that the wood trim is pretreated before applying the solvent ink. Bleach-free pretreatment is particularly preferably possible, but it is also possible for the wood trim part to be pickled alternatively or in addition to a bleach-free pretreatment.

Particularly preferably, the wood trim part is pretreated thermally and / or by irradiation, in particular by irradiation with electromagnetic radiation, prior to application of the solvent ink. This is preferably carried out in such a way that an aging process of the wood trim part, in particular a discoloration and / or a change in the surface structure, is accelerated and particularly preferably completed. This means, in particular, that the pretreatment is preferably carried out until no or only slight discoloration or change in the surface, in particular the visible surface, of the wood trim part occurs. Irradiation with electromagnetic radiation can be carried out in particular with light, preferably with UV light. Optionally, the pretreatment may also include subjecting the wood trim part to a predetermined humidity, in particular to make the aging process gentle, crack-free and uniform.

According to one embodiment of the invention, it is provided that the wood trim part is dried after the application of the solvent ink and before the application of the water-based ink. In particular, the wood trim part is dried through in the region of the drawn-in solvent ink. In this case, the drying is carried out in particular such that, on the one hand, the remaining wood still has enough residual moisture so as not to become brittle and / or tearing, and, on the other hand, there is not too much liquid for the subsequent entry of the water-based ink. In particular, such an undesirable and uncontrolled course of the water-based ink is avoided.

According to one embodiment of the invention, it is provided that the wood trim part is formed after the application of the water-based ink. In this way, the wood trim can be given any shape. For this process, the inks used must be heat-stable and formable, that is, during the forming no cracks and the Umformstellen remain evenly colored, and the colors must remain non-destructive despite the effect of heat. Color systems which are stable to heat preferably have inorganic pigments. The inks used must also be moisture-permeable so that the process moisture required for the forming process can be set.

Drying times for the inks can be shortened or replaced in the manufacturing process by the heat in a forming press. Thus, another advantage also arises over a stain color, in which the drying time can not be combined with a further process step.

Preferably, the wood trim part is moistened before forming, whereby the deformation can be carried out more easily and in particular process-safe. It is alternatively or additionally possible that the wood trim part is moistened during the forming.

According to one embodiment of the invention, it is provided that a polymerizable water-based ink is used as the water-based ink. The water-based ink is preferably polymerizable in such a way that, after curing, it does not show any reaction with a moist atmosphere during forming, wherein no color loss is to be feared. When reshaping the wood trim, the pigments of the water-based ink can move back and forth, so there is no risk of cracking in the color up to a failure of the wood.

The pigments of the solvent ink and / or of the water-based ink preferably have a diameter which is less than half the wavelength of the visible light, ie in particular less than at least half of 420 nm to at most half of 780 nm. Preference is given to using nanoscale pigments , which preferably have a diameter of at least 50 nm to at most 200 nm. Such pigments have the property of being transparent, so that the desired transparency of the wood structure is not affected by the color.

According to a development of the invention, it is provided that as solvent ink and as water-based ink, inks are used which have a surface energy of at least 28 mJ / m ² to at most 30 mJ / m ² , the inks preferably having a surface energy of 29 mJ / m ² exhibit. Such inks are suitable in a particularly favorable manner for application to a wood trim and in particular also to one another, in which case they can move into the wood trim, in particular in the area of the visible surface.

According to a development of the invention, it is provided that as solvent ink and as water-based ink, inks are used which have a viscosity of at least 3 mPas to at most 6.5 mPas, preferably from at least 3.5 mPas to at most 6 mPas.

It turns out that the inks, especially the coloring ink - such as CMYK inks and / or spot colors - should not bleed, the chemical and rheological composition of the inks must be matched to the wood of the wood trim. These include that the viscosity, surface energy and chemical reactivity must allow the inks to cure and / or dry faster than they run on the substrate. Alternatively, the liquid can also be drawn in as desired, but the pigments should settle at the sites to which they were applied.

According to one embodiment of the invention, it is provided that the inks are introduced into the visible surface with a penetration depth of at least 5 μm to at most 100 μm, preferably to at most 50 μm, preferably to at most 25 μm, preferably from at least 10 μm to at most 20 μm , This results in a near-surface introduction of the inks, which in particular ensures that on the one hand small amounts of inks can be used, on the other hand bleeding of the inks is not to be feared.

According to one embodiment of the invention, it is provided that the solvent ink of at least 10 ml / m ² to at most 110 ml / m ² , preferably of at least 15 ml / m ² to at most 100 ml / m ^{2 are} applied. Additionally or alternatively, it is provided that the water-based ink of at least 10 ml / m ^{2 are applied} to at most 50 ml / m ² , preferably from at least 15 ml / m ² to at most 45 ml / m ² . The amount of inks to be entered is thus kept relatively low, which has both cost advantages and advantages in terms of precision of printing the wood trim.

Finally, the object is also achieved by providing a vehicle having a wood trim part obtainable by one of the previously described embodiments of the method. Preferably, the wood trim part is colored according to one of the previously described embodiments of the method. In connection with the vehicle, in particular, the advantages which have already been explained in connection with the method are realized.

The wood trim part is preferably arranged in an interior of the vehicle, wherein the visible surface of the wood trim part faces an occupant of the vehicle.

In connection with the invention, in particular with the method, the following also appears:
It is preferably a pigmented, lightfast, heat-resistant after inking ink system surface and evenly on a flat wood veneer applied as a wood trim before a forming process. The ink system has the chemical properties to draw into the wood structure, so that no material application and no overlap of the surface take place, and the appearance of the real wood surface remains intact, especially for trim parts made of open-pore wood or with a thin lacquer layer.

This means that the ink sinks completely into the wood, keeping the amount of entry low and, in addition, the surface structure is not affected or roughened by swelling or the setting up of fibers. The material entry remains close to the surface. In order to make this possible, the ink requires special properties in terms of its viscosity and chemical composition, as well as its surface energy, so that a suitable bleeding results at the same time for the wood optimal reaction behavior. The wood is not changed chemically.

Specifically, this means that the pigments of the ink are sucked into the wood via the liquid solvent-binder system, of which inks generally consist, similar to pickling, whereby the solvent evaporates or repels. What remains is the dried or crosslinked by color pigments-binder composite, which can be put into the wood structure and partially bind to the wood components. Such properties are met by water-based inks and solvent inks. For the further manufacturing process of the wood trim, this means that the wood trim can be formed without cracking, since the pigments move in the wood, as long as the wood itself does not tear on the surface.

The incorporated inks must not seal the surface against water, since the subsequent forming process works reliably only when moisture is introduced, which is why preferably no glaze is used.

The properties described herein as advantageous are met by ink systems such as solvent inks on the one hand and water-based inks on the other hand. These can be applied in particular after a priming and drying of a veneer in the digital printing process. The drying is advantageous because otherwise there is too much liquid in the fibers, which can bring the newly applied ink to bleed, since it can no longer be absorbed.

The method proposed here makes it possible to print on a high-quality wood trim part, in particular for further processing in the production process of the wood trim part for the automotive sector. A favorable and defined coloring as through patterns, gradients and images, in addition to the option, wood coloring for pickling or dyeing, possible. Depending on the ink system, in particular with regard to solvent inks and water-based inks, a high quality of color and / or precision for a novel, defined decorative printing is possible. Even in a combination with a thermal pretreatment, a pre-priming and / or pickling, a defined in shape and color coloring is possible.

The invention will be explained in more detail below with reference to the drawing. The single figure shows a schematic representation of an embodiment of the method in the manner of a flow chart.

The single figure shows a schematic representation of an embodiment of the method for coloring wood trim parts for vehicles in a flow chart. In a first step S1, a wood trim part is provided, which is preferably designed as a veneer. In this case, the veneer can be laminated on a carrier, wherein preferably a laminating fleece can be arranged between the carrier and the veneer.

In a second step S2, a pretreatment of the wood trim part, in particular a bleach-free pretreatment, is preferably carried out. In particular, it is possible for a thermal pretreatment and / or a pretreatment to be carried out by irradiation with electromagnetic radiation, in particular with UV radiation. Alternatively or additionally, a pickling of the wood trim is possible.

In a third step S3, a solvent ink is applied to a visible surface of the wood trim area. In particular, the wood trim part is preferably primed in the region of the visible surface with the solvent ink. In this case, a white solvent ink is particularly preferably used, so that the wood trim part is primed white on the visible surface.

In a fourth step S4, a water-based ink is applied to the solvent ink at least regionally, in particular locally. Specifically, the water-based ink is applied to the solvent ink in the form of a pattern such as a geometric pattern, a pictogram, an image, a text, or the like. In particular, the wood trim is partially printed in the area of the visible surface on the solvent ink with the water-based ink.

It is also possible that the wood trim part in a process step, not shown, between the third step S3 and the fourth step S4, that is, after the application of the solvent ink and dried before applying the water-based ink.

In a fifth step S5, the wood trim part is preferably moistened, wherein it is preferably transformed in a sixth step S6. As a result, a molded part is produced in particular from the wood trim part.

It is possible for the wood trim part to be back-injected in a seventh step S7, with the back injection taking place, in particular, on a side of the wood trim part facing away from the visible surface, ie in particular in the area of a rear face facing away from the visible surface.

In an eighth step S8, a decor carrier or an adhesion promoter is preferably applied to the visible surface and in particular to the water-based ink, wherein, for example, a film can be used.

In a ninth step S9, a cover and / or protective lacquer is preferably applied to the visible surface, in particular to the water-based ink and / or on the decor carrier or adhesion promoter, wherein the topcoat and / or protective lacquer may in particular comprise polyurethane and / or polymethylmethacrylate.

It is possible that the wood trim part is finished in a tenth step S10.

Preferably, a polymerizable water-based ink is used. The solvent ink and the water-based ink preferably have a surface energy of at least 28 mJ / m ² to at most 30 mJ / m ² , preferably 29 mJ / m ² . The solvent ink and the water-based ink preferably have a viscosity of at least 3 mPas to at most 6.5 mPas, preferably from at least 3.5 mPas to at most 6 mPas. The inks are preferably introduced into the visible surface with a penetration depth of at least 5 μm to at most 25 μm, preferably of at least 10 μm to at most 20 μm.

Of the solvent ink are preferably applied from at least 10 ml / m ² to at most 110 ml / m ² , preferably from at least 15 ml / m ² to at most 100 ml / m ² on the visible surface. At least 10 ml / m ² to at most 50 ml / m ² , preferably from at least 15 ml / m ² to at most 45 ml / m ² are preferably applied from the water-based ink.

The thus produced and in particular colored wooden trim part is preferably used in a vehicle, in particular in a vehicle interior.

It turns out that by means of the method proposed here in particular a veneer for the implementation of new design concepts can be printed, thereby only high quality printing results are possible, which meet in particular the following claims:
The color scheme looks natural, that is, the wood of the veneer is to be discolored, so it is not just a superficial color layer to be applied. The latter happens, for example, in the printing with UV-curing systems, with a closed film forms on the wood surface, which adheres more or less mechanically or chemically depending on the substrate.

It is a high precision achievable, so that a passenger even on a long drive with extensive consideration still takes pleasure in the wood trim. This means in particular that he does not discover any pixels, dots or the like.

The wood grain remains visible, and the surface structure, which is responsible for the light reflection specific to wood, remains intact. The coloring should affect the structure at most slightly.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102014011138 A1 [0002]

Claims (10)

Method of coloring wood trim parts for vehicles, comprising the following steps: - Surface application of a solvent ink on a visible surface of a wood trim, and - Applying a water-based ink at least partially on the solvent ink. A method according to claim 1, characterized in that the water-based ink is applied locally, in particular in the form of a pattern. Method according to one of the preceding claims, characterized in that the wood trim part is pretreated before applying the solvent ink, in particular thermally and / or by irradiation. Method according to one of the preceding claims, characterized in that the wood trim part is dried after the application of the solvent ink and before the application of the water-based ink. Method according to one of the preceding claims, characterized in that a polymerizable water-based ink is used as the water-based ink. Method according to one of the preceding claims, characterized in that as solvent ink and as a water-based ink inks are used which have a surface energy of at least 28 mJ / m ² to at most 30 mJ / m ² , preferably of 29 mJ / m ² . Method according to one of the preceding claims, characterized in that as solvent ink and as water-based ink inks are used which have a viscosity of 3 mPas to at most 6.5 mPas, preferably from at least 3.5 mPas to at most 6 mPas. Method according to one of the preceding claims, characterized in that the solvent ink and the water-based ink in the visible surface with a penetration depth of at least 5 microns to at most 100 microns, preferably from at least 5 microns to at most 50 microns, preferably from at least 5 microns to at most 25th μm, preferably of at least 10 μm to at most 20 μm. Method according to one of the preceding claims, characterized in that from the solvent ink at least 10 ml / m ² to at most 110 ml / m ² , preferably at least 15 ml / m ^{2 are applied} to at most 100 ml / m ² , and / or that of at least 10 ml / m ² to at most 50 ml / m ² , preferably at least 15 ml / m ² to at most 45 ml / m ^{2 are} applied to the water-based ink. Vehicle, with a wood trim, obtainable by a process according to one of claims 1 to 9.

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