EP3508102A1 - Sanitary device blank and method for manufacturing the same - Google Patents

Abstract

Sanitary tub with a tub body (1) made of steel and one on the tub body (1) arranged coating of enamel, the invention essential to the coating having a laser beam generated macroscopic structures.

Description

The invention relates to a sanitary tub with a tub body made of metal and arranged on the tub body coating of enamel. The invention further relates to a sanitary tub blank, in particular for the formation of a sanitary tub according to the invention, and a method for producing.

Such combinations of a tub body made of steel and a coating of enamel thereon are generally also referred to as steel enamel. Sanitary baths made of steel enamel are characterized by high scratch, abrasion and impact resistance and are hygienic and dirt-repellent. In addition, the high-quality appearance of steel enamel remains long-term, even under the influence of chemical substances and heat no color or surface changes occur.

The production of enamel and enamelled products is known to the person skilled in the art. For this purpose, the " Rompp Chemie Lexikon ", Volume 2, 9th edition, 1990, p 1147 ff , such as " Ullmanns Encyklopadie der technischen Chemie ", Vol. 10, 4th Edition, 1975, pp. 436 to 447 directed.

As raw materials for the enamel production serve quartz, feldspar, soda, calcium carbonate, borax, sodium nitrate and fluorspar and aggregates according to the intended use. The raw materials are mixed and melted at about 1200 ° C and solidified, the frit is in the form of granules or scales.

The frit is ground and usually mixed with water to a slurry which is applied to the steel surface to be coated, usually a steel sheet. Before firing, the coating is dried, the dried layer being referred to as enamel biscuit or biscuit.

In the context of the invention, the blank is the intermediate product formed in this way before the final baking process. This is true even if in a multi-layered, typically two-layer application of enamel with a base enamel and a top enamel the base enamel layer is already baked and on the top enamel layer is present as a biscuit layer.

As a sanitary tub, for example, a bathtub or a shower tray into consideration. Under a tub is usually understood a body with a marginal boundary and a vessel-shaped depression arranged therebetween. The vessel-shaped depression also has primarily a slope, which opens into a drain opening. Within the scope of the invention, bodies are also referred to as tubs which deviate from the classical sense of the word. So it is conceivable, for example, that issued as a shower tray sanitary device consists of a substantially planar body, which has a concrete slope only by the installation situation, which is directed to a peripheral outlet. The seal is made by special sealing tapes. In general, therefore, a broad interpretation of the term tub is required.

In sanitary baths made of steel enamel, there is always the risk for the user to slip on the surface of the sanitary bath under the influence of moisture.

Here, a thin film of water is formed between the human skin and the surface, the emergence of surface-active substances, such as those contained in personal care products, such as shower gels, bath products, shampoos or skin care products, is favored again.

In order to design a surface slip-resistant, it is therefore already known to at least partially break through the production of edges and roughness of the surface film.

The US 2004/0105966 A1 describes in this context a sanitary tub made of metal with an enameled surface, the enamelled surface is provided in at least one section with an anti-slip slip-coating. The anti-slip coating consists of a granular inorganic material, which is firmly bonded to the enamelled surface by firing.

Alternatively, the describes DE 43 09 019 A1 a sanitary tub having a non-slip floor surface created by roughening. The roughening is done by blasting with corundum or glass beads, by etching, brushing or grinding. The method described is primarily suitable for pans made of acrylic glass, but should also be used for enamelled steel tubs. However, a mechanical material removal of enamelled surfaces in manufacturing terms is very complex. In addition, a mechanical material removal has the disadvantage that the high-quality enamelled surface is damaged.

In addition, anti-slip structures in accordance with the EP 0 825 917 B1 by generating micro-craters by means of a laser.

An appropriate application for steel enamel tubs is also from the DE 20 2016 003 216 known, wherein by means of the laser small depressions or elevations are introduced into the surface of the already formed shower or bath. Overall, however, this method is capable of improvement.

Based on a sanitary tub of the type described above, the invention has for its object to modify a sanitary tub so that it is easy to manufacture and has on the surface or on the surface that is entered by the user, particularly good slip-resistant properties.

This object is achieved by a sanitary tub according to claim 1, wherein the coating has macroscopic structures produced by a laser beam. Macroscopic structures in the context of the invention means a structure in the form of an elevation or depression, which has at least a length of 4 mm, preferably 10 mm or more and / or a base area of at least 1 mm ² .

The invention is based on the finding that the water film can be broken up in a targeted manner by such macroscopic structures. If the macroscopic structures are depressions, it is expedient for the macroscopic structures to be configured in such a way that the base area of the depression is suitable for receiving and / or dissipating at least part of the water quantity. For macroscopic structures in the form of elevations, then the valleys between the elevations should fulfill this task.

In a preferred embodiment of the invention, the structures are formed coherently. For example, a kind of channel system can then be created by the macroscopic structures, wherein the individual channels are either branched or arranged in series one behind the other. Furthermore, it is also possible to have such an arrangement of macroscopic structures which comprise a self-contained channel system, e.g. in the form of a rectangle or a circle.

The tub body has a slope, wherein the macroscopic structures can be aligned on this slope. By means of such an orientation, the macroscopic structures serving as channels can transport the water in a targeted manner to the discharge opening. It does not matter whether the macroscopic structures are coherent or not. If the macroscopic structures are non-contiguous, it is advisable to have an arrangement of several gutters arranged in a star shape around the outflow opening and formed in the form of depressions or two elevations arranged next to one another. In this case, the channels can be designed to be straight or, for example, wave-shaped or zigzag-shaped. When using coherent macroscopic structures, it can be provided that at least individual structures are aligned with the slope or run in the direction of the outflow opening. The macroscopic structures, which do not run in the direction of the gradient, can then preferably be branched off from at least one structure running in the direction of the outflow opening.

Often, however, transport of water through the described macroscopic structures is not critical. Rather, the provision of edges on which the water film is locally interrupted is regarded as essential becomes. Especially with linear structures, the effective edge length in a wavy course is decisive. In this context, it can also be observed that the generation of the macroscopic structures by means of lasers generally does not result in a straight but wavy edge course. A certain wavy structure and an associated irregularity is particularly advantageous for the interruption of a coherent water film. On the other hand, larger outbreaks should be avoided.

In order for the macroscopic structures to achieve a good slip-resistant effect, it is expedient that the macroscopic structures preferably have a depth in the range of 10 μm to 150 μm. The depth of the macroscopic structures is particularly preferably between 20 μm and 50 μm, in particular between 30 μm and 40 μm.

In the case of a linear configuration of the macroscopic structures, the width may be, for example, between 35 μm and 250 μm, a range between 70 μm and 130 μm being particularly preferred.

It should be noted that the specified values refer to a mean line width, the edges are not straight, but run with a certain wave or jagged shape. For example, if a line-shaped macroscopic structure having a line width of 85 μm is formed, the variation of the line width may typically be in a range between -8 μm and +15 μm. Such a variation of the line width can be easily accepted and is even advantageous because the irregular course increases the effective edge length.

It is also advantageous if the macroscopic structures have a mutual distance in the range of 1 mm to 20 mm, preferably in the range of 2 mm to 7 mm. This distance from one another is intended to ensure that a sufficient number of macroscopic structures can be arranged in a corresponding area section of the sanitary tub, so that the amount of water can also be effectively absorbed or transported away.

It is fundamentally within the scope of the invention that the macroscopic structures can be distributed over the entire surface of the sanitary tub. Preferably, however, macroscopic structures are provided only where a slip-resistant effect is required. For example, the edge areas of a sanitary tub can possibly do without such structures. The proportion of the surface of the sanitary tub, which is provided with macroscopic structures, is in the range of 5% to 100%, for example between 40% and 50%. Especially with shower trays, it may also be just advantageous if the entire surface is provided with macroscopic structures.

The invention further provides a sanitary tub blank according to claim 4, in particular for forming a sanitary tub according to the invention with a tub body made of steel and arranged on the tub body coating, wherein the coating has at least one unfired structural layer in the form of a biscuit layer. According to the invention, this sanitary tub blank is characterized in that the unfired structured layer is modified with a laser beam. The sanitary tub blank is to be understood in the context of the invention as a semi-finished product, from which an enameled sanitary pan can be formed.

The sanitary tub blank according to the invention is based on the finding that the unfired structured layer of enamel frits can already be modified with a laser in such a way that after a concluding firing process no further steps are required to form an anti-slip surface. In particular, can then be dispensed with a laser processing of the finished burned surface. As a result, the problem is avoided that the laser processing of an already finished topcoat this may possibly be damaged in such a way that a water impermeability is no longer present. According to the present invention, only the sanitary tub blank is processed, so that already possible damage can be compensated before the firing process. In addition, a modification of a sanitary tub blank in terms of process management is advantageous over the modification of a finished-fired sanitary tub.

According to the usual embodiment, the coating is formed at least one to three layers. In the case of a three-layer structure, the coating consists of a primer layer, a cover layer arranged thereon and a structure layer arranged on the cover layer, which is modified with a laser beam. In principle, however, it is also possible to form the coating only in two layers with a cover layer and a structural layer, in which case the cover layer is formed from so-called direct white. This is especially possible if the tub blank is made of nickel-plated steel. Finally, a single-layered construction is possible, in which case the macroscopic structures are then introduced with the laser in the still unfired layer of direct white. Especially in the case of a tub blank made of nickel-plated steel and a sufficiently thick biscuit layer of the not yet fired direct white, this is readily possible within the scope of the invention.

The laser can then be used to make various types of modifications to achieve slip-resistant structures in the green structural layer.

According to a first variant, the unfired structured layer has notches introduced with the laser beam. The laser beam thus follows a removal of ground enamel frits or the (dried) slip in the structural layer. For this purpose, the laser beam must have a sufficiently high energy. This is usually done by using a pulsed laser, such as a Nd: YAG laser or a CO ₂ laser. The laser energy is concentrated here on a short time pulse, so that for a short moment a very high laser power is available.

The depth of the notch is basically limited to the thickness of the structural layer, wherein preferably the structural layer has a thickness in the range of 100 microns to 200 microns. Since the cover layer arranged below the structural layer and optionally also a base layer should not be damaged during the modification by laser beam, however, a smaller depth of the notch is expedient, the structural layer having at least one residual layer thickness of z. B. should have 50 microns.

According to a further embodiment of the invention, a modification by laser can also be provided such that the structure layer is only partially fixed on the cover layer with the laser beam. In contrast to a full-surface arrangement of a structural layer with indentations introduced according to this variant, the structural layer is no longer arranged over the entire surface of the cover layer and thus forms on its own a slip-resistant surface in the form of elevations on the Top layer. Also in this case, both an at least two-layer construction with a cover layer of direct white as well as a three-layer structure with an additional primer layer is possible. The fixation of the structural layer on the cover layer takes place in such a way that the enamel frits of the structural layer are partially melted with the laser beam and thereby solidified. The non-solidified regions of the structural layer can then be removed, in which case the solidified regions remain in the form of elevations on the covering layer.

In contrast to the modifications already known from the state of the art, macroscopic structures, such as channels, for example, can be inserted or applied into the sanitary tub blank, which are formed in a particularly preferred manner in a coherent manner. There is thus a complete modification of the sanitary tub blank, which is then formed by a final fire to a finished sanitary tub. Subsequent processing of the fired structural layer is not required.

In addition to a sanitary tub and a sanitary tub blank, a method for producing a sanitary tub according to claim 9 is part of the invention. Here, a sanitary tub blank is first formed such that on a body made of steel, a coating of enamel is applied with an unfired structural layer, wherein the unfired structural layer is then modified by means of a laser beam. For this purpose, the coating typically has a one-to three-layered construction. In the case of an at least three-layered structure, a primer layer is first applied to the tub body and then a cover layer is applied to this primer layer. Between the application of the individual layers is usually a firing process for fixing the individual layers on the tub body. The unfired structure layer of enamel frits is then applied to the cover layer and then modified with a laser beam.

If the coating is made in two layers, the cover layer can be applied directly to the tub body. An additional primer layer is therefore not required. In this method, a cover layer of so-called direct white is used. Further, the tub body must be a tub body of nickel plated steel.

A two-layered construction is also possible if initially a primer layer is applied and baked before the structuring described then takes place in a sufficiently thick cover layer. The cover layer then coincides with the structuring layer.

Finally, even with the use of nickel-plated steel and a sufficiently thick layer of direct white in a comparable manner, a single layer and thus a single firing process is sufficient.

The application of the coating or of the individual layers of the coatings can be carried out by means of all known from the prior art application method, which of course - as in the structural layer - the enamel in the form of ground enamel frit or as a liquid slip in a spray applied wet, dried and then fired. To produce slip-resistant structures, the cover layer is then modified with the laser, with two different modification methods have proven to be useful, which have already been described in connection with the sanitary tub.

According to a first variant, material is removed by the laser beam and, as a result, notches are produced in the unfired structural layer. For this purpose, preferably lasers are used which generate a pulsed laser beam, such as Nd: YAG laser or CO ₂ laser. In this case, it is basically possible to focus the laser beam and then direct it directly onto the unfired structural layer.

According to a second variant of the method, the laser beam partially melts and solidifies material of the unfired structural layer. In contrast to the previous method, there is thus no removal of material or no appreciable removal of material, but only a partial fixation of the structural layer as a result of the action of heat by the laser beam. As a result of the area-wise fixing, solidified and non-solidified areas thus form in the unfired structural layer, the non-solidified areas furthermore being mechanically sensitive to external influences.

To form slip-resistant structures, the non-solidified material is therefore preferably subsequently removed, in particular blown off. In principle, however, a rinse by water or a brushing is possible.

By removing the non-solidified material, the unfired structure layer forms elevations on the cover layer, through which the water film is deliberately broken. It goes without saying that then the unfired structural layer is also arranged only in the areas on the cover layer, in which previously the structural layer was also solidified. Thus, the cover layer can be partially exposed, so that the coating minus a possible primer layer is formed partially monolayer and two-layer.

In a preferred embodiment of the invention, the unfired structural layer is applied only in regions on the cover layer. In this approach, the considerations play a role that only there, the application of an unfired structural layer is required, in which also subsequently a slip-resistant structure is to be achieved by modifying the green structure layer. In this regard, for example, special order masks are possible, which only allow the application of the structural layer in which a corresponding opening is provided. In a particularly advantageous manner, the material used can be significantly reduced thereby.

Subsequently, the unfired structural layer is fired, forming a finished sanitary tub. In a preferred embodiment of the invention, the unfired structural layer is first heated to a temperature between the glass transition temperature and the softening point of the enamel before being fixed with the laser beam. This procedure offers the advantage that only a comparatively low energy has to be applied with the laser beam in order to fix the unfired structured layer, since a substantial part of the temperature increase already takes place through the additional heating process. With the laser beam, only the threshold for fixing is then exceeded, without a significant input of energy for a temperature increase is required.

After the modification of the unfired structural layer either in the form of notches or in the form of a region-wise fixation then the Sanitärwannenrohling preferred final fired, so that a finished sanitary tub is formed.

In a preferred development of the invention, the unfired structure layer is modified with the laser beam in such a way that macroscopic structures, in particular coherent macroscopic structures, such as e.g. branched or closed grooves are created in the structural layer. Such structures can be produced, for example, in such a way that the laser or laser beam is guided along a predetermined direction and macroscopic structures in the form of grooves formed thereby are formed by indentations in the cover layer or two mutually adjacent solidified regions in the structural layer.

However, the formation of coherent macroscopic structures is not limited to the previously described process control types, but can also be applied, for example, to a ready-made sanitary pan, in particular a steel enamel pan, in which case the coherent macroscopic structures are introduced into the fired top layer by means of a laser.

Fig. 1

Duschwanne mit makroskopischen Strukturen,

Fig. 2a, 2b, 2c

die Verfahrensschritte zur Bildung einer mittels Einkerbungen modifizierten Strukturschicht,

Fig. 3

eine alternative Ausgestaltung einer Sanitärwanne gemäß den Fig. 2a, 2b, 2c,

Fig. 4a, 4b, 4c

die Verfahrensschritte zur Bildung einer bereichsweise auf einer Deckschicht fixierten Strukturschicht,

Fig. 5

eine alternative Ausgestaltung in einer Schnittansicht.

The invention will be explained in more detail with reference to a drawing showing only one exemplary embodiment. Show it:

Fig. 1

Shower tray with macroscopic structures,

Fig. 2a, 2b, 2c

the method steps for forming a notch-modified structural layer,

Fig. 3

an alternative embodiment of a sanitary tub according to the Fig. 2a, 2b, 2c .

Fig. 4a, 4b, 4c

the method steps for the formation of a structural layer fixed in regions on a cover layer,

Fig. 5

an alternative embodiment in a sectional view.

The Fig. 1 shows an example of a shower tray with a square base and a centrally arranged drain 11. From the tub rim 12 to the drain opening 11, the shower tray on a slope.

This is a shower tray, which is made of steel enamel and thus has a coating of enamel. In this coating, macroscopic structures generated with a laser beam are also applied and / or applied, wherein these macroscopic structures can be designed differently. Trough-shaped or linear structures are particularly preferred. According to the in Fig. 1 Sanitary trough pictured above, this can be realized for example in the form of straight line-shaped structures, for example in the form of channels. If these are aligned with the slope and extend in the direction of the drain opening 11, the water can be transported in a targeted manner in the direction of the drain opening 11. Furthermore, wave-shaped channels are also conceivable or channels which have a zigzag-shaped structure. More important than the orientation on a slope, however, is the formation of an edge, which can locally break a film of water. In this context, in particular the effective edge length is decisive, wherein a not completely straight, but a slightly wavy or jagged edge of the macroscopic structures is advantageous.

The Fig. 1 further shows macroscopic structures formed integrally. According to the upper figure, the sanitary tub has exemplary linear macroscopic structures, which are formed both in the direction of the drain opening 11 and also parallel thereto, wherein these structures can merge into one another or intersect.

The figure below shows macroscopic structures that are closed so that, for example, rectangles or circles are created. Furthermore, it is shown that the macroscopic structures can also be arranged only in regions on the surface of the sanitary tub.

The Fig. 2a, 2b, 2c show in this context how these macroscopic structures can be formed.

According to the Fig. 2a is disposed on the tub body 1, a primer layer 2, wherein in a first process step, the primer layer 2 is applied to the tub body 1 and then fired in a kiln. In this case, the primer layer 2 solidifies and is fixed on the tub body 1. In a next step, a cover layer 3 is then applied to the primer layer 2 and fired again. Subsequently, a structure layer 4 of ground enamel frit is applied to the cover layer 3 by means of a spraying process on the cover layer 3.

Then takes place according to Fig. 2b the modification of the structure layer 4 by means of a laser 5, which acts on the structure layer 4 with a laser beam 6 such that indentations 7 form within the structure layer 4. By the laser beam 6, the material of the structure layer 4 is partially removed, wherein the laser beam 6 is pulsed to achieve a high energy density.

Depending on the power of the laser 5 or on the strength of the laser beam 6 and depending on the duration of the action time of the laser beam 6 in the structure layer 4, indentations 7 of different depths can be produced, wherein the depth of the indentations 7 is limited by the layer thickness of the structure layer 4. The proviso that the depth of the notches 7 may only be so large that in the region of the notches 7 in the structural layer 4, a sufficient residual thickness remains. If the structural layer 4 is intended to cover the underlying layer in color, then a residual thickness of more than 80 μm is preferably provided. If a color coverage is not necessary, the residual thickness can also be readily smaller.

As soon as all notches 7 within the structure layer 4 have been produced with the laser 5, in a next method step according to FIG Fig. 2c the plumbing tub blank with the tub body 1, the primer layer 2, the cover layer 3 and the structural layer 4 are fired, whereby the structural layer 4 is solidified and is fixed as it were with the notches 7 on the cover layer 3. As a result, a ready-to-use sanitary tub is formed by the burning process, which has an anti-slip structure on the surface through the notches 7. In order for the slip-resistant structure to be as effective as possible, the notches 7 have an average width in the range between 70 μm and 130 μm with a preferably (slightly) wavy edge, the individual notches 7 being arranged at a distance of 2 mm to 7 mm.

For better visibility, the FIGS. 2b to 3 not shown proportionally.

According to the Fig. 3 is in such a process, in which the structural layer 4 is modified by the introduction of notches 7, a merely two-layer structure of the coating sufficient, so that in principle can be dispensed with a primer layer 2. In such a case, the tub body 1 formed of steel is additionally nickel-plated on the surface, and the material used for the cover layer 3 is so-called direct white enamel.

The method steps for forming such a sanitary tub with a coating without a primer layer 2 essentially correspond to the steps already presented in a three-layer coating according to FIGS Fig. 2a, 2b, 2c , wherein the pre-applied in the figures applying a primer layer 2 and the subsequent firing of the primer layer 2 is omitted.

Instead of indentations 7, the structure layer 4 can also be modified in another way by means of a laser beam 6, which also forms slip-resistant structures in the coating. This is done according to Fig. 4a analogous to Fig. 2a First, a primer layer 2 applied to the tub body 1 and then fired. Subsequently, a cover layer 3 is then applied to the fired primer layer 2, fired and finally applied a structural layer 4, wherein also here the structural layer 4 consists of enamel frits. As a result, a three-layer coating of fired primer layer 2, a fired top layer 3 and an unfired structural layer 4 is thus formed.

In a next method step is then according to the Fig. 4b generated by the laser 5, a laser beam 6 and directed to the surface of the structural layer 4. The type of laser type and also the choice of the power of the laser radiation is here dimensioned such that no appreciable material removal takes place, but that the structure layer 4 is heated by the action of the laser radiation 6 and thereby fixed. Thus, starting from the point of impact of the laser beam 6, regions are formed in which material 8 solidified by the laser radiation 6 is present and regions which are not under the action of the laser beam 6 and thus have non-solidified material 9.

Subsequently, in a method step according to Fig. 4c the removal of the non-solidified material 9 of the structural layer 4. The removal is carried out for example by blowing off with air or other gaseous medium, by rinsing with water or by brushing. Then, the structural layer 4 is present only by the material 8 solidified by means of laser 5 or laser beam 6, wherein a complete removal of the non-solidified material 9 is not absolutely necessary. In principle, it is also possible that the structure layer 4 is only partially freed from the non-solidified material 9, so that then the non-solidified material 9 is fixed in a final firing process. In the present case, however, the non-solidified material 9 has been completely removed and the structural layer 4 forms a partially present structure on the cover layer 3.

The Fig. 5 shows an embodiment of the sanitary tub, in which the coating is formed only one layer. For this purpose, the designated direct white enamel is applied as a slurry in sufficient thickness and dried, in which case the structuring is carried out directly in the biscuit layer thus formed. The cover layer 3 thus simultaneously forms the structural layer 4 with the notch 7.

Claims (19)

Sanitary tub with a tub body (1) made of steel and a on the tub body (1) arranged coating of enamel, characterized in that the coating has macroscopic structures produced by a laser beam. Sanitary tub according to claim 1, characterized in that the structures are formed contiguous. Sanitary tub according to claim 1 or 2, characterized in that the macroscopic structures have a depth in the range of 10 microns to 150 microns. Sanitary tub blank for shower or bath tubs, in particular for forming a sanitary tub according to one of claims 1 to 3, having a tub body (1) made of metal and a coating of enamel arranged on the tub body, the coating having at least one unfired structured layer (4), characterized in that the unfired structure layer (4) is modified with a laser beam (6). Sanitary tub blank according to claim 4, characterized in that the coating has a cover layer (3), on which the unfired structural layer (4) is arranged. Sanitärwannenrohling according to claim 4 or 5, characterized in that the unfired structure layer (4) with the laser beam introduced notches (7). Sanitärwannenrohling according to claim 5 or 6, characterized in that the unfired structural layer (4) is only partially fixed on the cover layer (3) with the laser beam (6). Sanitärwannenrohling according to claim 5 to 7, characterized in that the unfired structural layer (4) has a thickness in the range of 100 microns to 200 microns. Method for producing a sanitary tub, wherein firstly a sanitary tub blank is formed in such a way that an enamel coating with an unfired structured layer (4) is applied to a tub body (1) made of steel, the unfired structured layer (4) being irradiated with a laser beam (6) is modified. A method according to claim 9, wherein the coating comprises a cover layer (3) disposed either on a primer layer (2) or on the tub body (1), first applying and firing the cover layer (3) and then the unfired structural layer (3). 4) is applied to the cover layer (3). Method according to claim 9 or 10, wherein material is removed by the laser beam (6) and indentations (7) are produced in the unfired structured layer (4). Method according to one of claims 9 to 11, wherein by the laser beam (6) partially material of the green structure layer (4) is melted and solidified. The method of claim 12, wherein the non-solidified material (9) of the unfired structural layer (4) is at least partially removed, The method of claim 13, wherein the non-solidified material (9) of the unfired structural layer (4) is blown off. Method according to one of claims 9 to 14, wherein the unfired structural layer is applied only in regions on the cover layer. Method according to one of claims 12 to 15, wherein the unfired structural layer (4) is first heated prior to fixing with the laser beam (6) to a temperature which is between the glass transition temperature and the softening point of the enamel. The method of any one of claims 9 to 15, wherein the sanitary tub blank is finally fired. Method according to one of claims 9 to 17, wherein the unfired structural layer (4) is modified with the laser beam (6) in such a way that macroscopic structures are produced in the unfired structural layer (4). A method according to claim 9, wherein the structural layer (4) also forms the cover layer (3) in a single firing operation.

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