Method and device for producing a printed concrete element, and printed concrete element

Abstract

The invention relates to a method for producing a printed concrete element (1), in particular a printed concrete block, a printed concrete panel or a printed concrete step, the method comprising at least the following steps: - printing at least one visible face (2) of the concrete element (1), wherein the printing of the concrete element (1) is carried out when the concrete element (1) is in a green-strength state in which the concrete element (1) is non-deformable but not yet cured, and - curing the concrete element (1) after the printing process. According to the invention, a) the printing takes place using a first printing composition (10) substantially consisting of chromophoric inorganic pigments and a binder-free solvent, or b) the printing takes place using a second printing composition (10) substantially consisting of chromophoric inorganic pigments and a binder-free solvent mixture, or c) the printing takes place using a third printing composition (10) substantially consisting of chromophoric inorganic pigments, polyacrylate as a binder and a solvent or solvent mixture.

Description

[0001] METHOD AND DEVICE FOR PRODUCING A PRINTED CONCRETE BODY, AND PRINTED CONCRETE BODY

[0002] This application claims priority from German patent application No. 10 2022 127 582.5, the contents of which are incorporated herein by reference.

[0003] The invention relates to a method for producing a printed concrete body, in particular a printed concrete block, a printed concrete slab or a printed concrete step according to the preamble of claim 1.

[0004] The invention further relates to a device for producing a printed concrete body according to claim 15.

[0005] Furthermore, the invention relates to a printed concrete body.

[0006] Printing on concrete, especially concrete blocks, has proven to be a suitable method for imparting a colorful design to the concrete. In particular, there is a need to design the visible surface of the concrete block in such a way that it resembles or imitates natural stone. However, when printing on concrete blocks, a number of challenges must be considered, such as the difficulty of achieving good adhesion of the print to the concrete.

[0007] The known methods for printing concrete bodies are primarily based on the so-called dry printing process. In this process, the concrete body is printed after it has hardened to apply a pattern to the visible surface or to add color.

[0008] It has been shown that printing on uncured, wet concrete can be particularly advantageous, as the printing compounds used for printing can flow into the concrete, resulting in patterns and structures that cannot be achieved with the dry printing process. However, the printing compounds used for this purpose must be selected in such a way that they exhibit good adhesion to the concrete body that will subsequently cure and are compatible with the curing conditions of the concrete body.

[0009] A generic method is known from DE 10 2017 005 280 B4.

[0010] DE 102017 005 280 B4 proposes a method for producing a printable concrete body. This method involves pouring concrete into a mold to form a concrete body. Subsequently, a visible surface of the concrete body is printed with a printing composition comprising a binder A and a dye B, wherein the binder A contains at least one siloxane and one silane, and wherein the siloxane is a condensed, pre-crosslinked silicone resin. After printing, the concrete body is cured. For further prior art, reference is also made to DE 10 2006 014 900 A1.

[0011] DE 10 2006 014 900 A1 describes a wet printing process for concrete bodies. The concrete product described therein has a print embedded in the concrete on a visible surface. The printing is carried out on wet concrete, which has not yet set or has only partially set. DE 10 2006 014 900 A1 does not address a printing composition or the flow of the printing composition on the wet concrete. Therefore, DE 10 2006 014 900 A1 does not disclose how flowing patterns can be achieved on and / or in the concrete. Furthermore, the document does not address the problem of the material's adhesion to the hardened concrete or the properties that the printing composition must fulfill to ensure that the printing composition does not lose its desired structure during thermal hardening of the concrete body.

[0012] Based on the state of the art, it would be desirable to provide a method and device for printing concrete bodies that would allow for a simple, reliable, and cost-effective way to permanently impart an aesthetic design to the visible surface of a concrete body. It would also be desirable if the method and device could be integrated into existing plant concepts, especially into existing plants for the production of concrete bodies.

[0013] The methods known from the prior art, such as DE 10 2017 005 280 B4, generally involve the use of a so-called primer, which is applied to the visible surface of the concrete body and provides a white surface that can then be printed. While the white surface provided by the primer allows for a good print image, particularly for displaying colors, it has the disadvantage that if the visible surface is manually damaged, the white primer underlying the print becomes clearly visible, permanently impairing the appearance of the concrete body.

[0014] The present invention is based on the object of creating a method for producing a printed concrete body with which a visible surface of the concrete body can be printed in a particularly advantageous manner in order to give the concrete body an aesthetic appearance that is resistant to weather conditions at low cost.

[0015] This object is achieved according to the invention by the features of claim 1.

[0016] The present invention is further based on the object of creating a device for producing a printed concrete body, with which a visible surface of the concrete body can be printed in a particularly advantageous manner in order to cost-effectively impart to the concrete body an aesthetic and weather-resistant appearance. This object is achieved according to the invention by the features of claim 15.

[0017] The present invention is further based on the object of providing a printed concrete body which has an aesthetically pleasing and cost-effectively producible visible surface which is resistant to weather conditions.

[0018] This object is achieved according to the invention by claims 16 and 17.

[0019] The method according to the invention for producing a printed concrete body, in particular a printed concrete block, a printed concrete slab or a printed concrete step, comprises at least the following steps:

[0020] Printing on at least one visible surface of the concrete body, wherein the printing of the concrete body is carried out in a green state of the concrete body in which the concrete body is dimensionally stable but not yet hardened, and

[0021] Curing of the concrete body after printing.

[0022] According to the invention, it is provided that the printing is carried out with a first printing composition, essentially consisting of color-providing inorganic pigments and a binder-free solvent, or the printing is carried out with a second printing composition, essentially consisting of color-providing inorganic pigments and a binder-free solvent mixture, or the printing is carried out with a third printing composition, essentially consisting of color-providing inorganic pigments, polyacrylate as a binder and a solvent or a solvent mixture.

[0023] A green-strength concrete body is one that is dimensionally stable but not yet hardened or fully set. In particular, this refers to a concrete body that has not yet been transferred to a setting room or a setting chamber / drying room for complete curing.

[0024] A green-strength concrete body is understood to mean, in particular, a concrete body in which the main compaction process has been completed, but which has not yet set or has not yet completely set.

[0025] A concrete body in its green state is also referred to in the art as a "green" concrete blank. The green state of the concrete body means that the concrete body has already hardened to such an extent that it retains its shape when it leaves the production mold or the filling mold, or when it is removed from the mold.

[0026] The printing on the visible surface of the concrete body is therefore carried out while the visible surface of the concrete body is still damp or wet. It has been shown that printing on the concrete body when it is in a green state is particularly advantageous because the ink or printing composition used for printing penetrates well or deeply into the concrete and flows. Although this can mean that precise structures cannot be printed with the same sharpness as is possible with a dry printing process, it has been found to be advantageous for creating a natural stone look, a wood look, a textile look, a tile look or a mosaic look if the ink or the printing composition runs somewhat horizontally and / or vertically, i.e. in the plane of the visible surface (= horizontal) and orthogonal (= vertical) to it.

[0027] It has been shown that by printing on a concrete body in a green state, a print that is also resistant to weathering conditions can be achieved, in particular because the print or the ink / printing composition can penetrate relatively deeply into the concrete of the concrete body.

[0028] Surprisingly, it has been shown that a printing composition consisting essentially of color-providing inorganic pigments and a binder-free solvent or a binder-free solvent mixture is particularly suitable for printing the visible surface of the concrete body.

[0029] The coloring pigments can be, in particular, iron oxide pigments (red, yellow, black), cobalt oxide pigments (blue, green) and / or titanium oxide pigments (white).

[0030] In contrast to the teaching of DE 10 2017 005 280 B4, which explicitly recommends the use of a binder, whereby the binder should contain a siloxane and a silane, it has been found that particularly good printing results can be achieved without the use of a binder or by using a binder-free solvent or a binder-free solvent mixture, whereby the printing composition penetrates so deeply into the concrete composition in the horizontal and / or vertical direction that even if the visible surface is damaged, the applied pattern remains recognizable and the desired appearance is thus retained.

[0031] It has also been shown that particularly good printing on the visible surface of the concrete body can be achieved using color-giving inorganic pigments.

[0032] The solvent or solvent mixture used with the inorganic pigments can, if desired, also contain a binder; in this case, however, the solvent or solvent mixture must at least be siloxane-free and / or silane-free and / or resin-free, i.e. the solvent or solvent mixture must not contain any siloxane, silane, or resin. Tests have shown that good, durable printing can also be achieved with a printing composition (third printing composition) consisting essentially of color-imparting inorganic pigments, polyacrylate as a binder, and a solvent or solvent mixture. This means that it has been found that, when a binder is used, polyacrylate is particularly suitable as a binder for achieving suitable, high-quality printing.

[0033] It is advantageous if the coloring pigments are UV-resistant.

[0034] According to the invention, it can be provided that the solvent does not contain any water or is not an aqueous system.

[0035] The solvent may in particular be selected from a group consisting of alcohols or esters or petroleum spirits or aromatic solvents.

[0036] The solvent mixture preferably consists of water as well as alcohols, esters, petroleum spirits, aromatic solvents and mixtures thereof.

[0037] According to the invention, it has further been found to be advantageous if the first printing composition consists of 10% by weight to 90% by weight of the solvent and the coloring pigments.

[0038] It has proven particularly suitable if the solvent makes up 50 wt.% to 90 wt.%, in particular 60 wt.% to 80 wt.%, of the first printing composition, i.e., the coloring pigments particularly preferably make up 20 wt.% to 40 wt.% of the first printing composition. In particular, it can be provided that the first printing composition comprises or consists of 70 wt.% to 80 wt.% of the solvent and correspondingly 20 wt.% to 30 wt.% of the coloring pigments, optionally excluding unavoidable residual impurities.

[0039] It is advantageous if the second printing composition comprises a solvent mixture with a water content of 10 wt.% to 90 wt.%. In particular, it can be provided that the second printing composition consists of 20 wt.% to 40 wt.% of the coloring pigments and 20 wt.% to 40 wt.% of water, with the water being a component of the solvent mixture, and the remaining components of the solvent mixture are then formed or selected accordingly, so that the solvent mixture makes up a total of 60 wt.% to 80 wt.% of the second printing composition.

[0040] The second printing composition may consist of 20% to 40% by weight of the coloring pigments and 60% to 80% by weight of the solvent mixture, with the solvent mixture consisting of one-third to two-thirds by weight of water. The inventors have recognized that the following three printing compositions are particularly suitable for producing a printing composition.

[0041] The first printing composition may consist of a solvent with inorganic pigments, wherein the solvent does not contain water or is not an aqueous system and the solvent, preferably a hydrophilic solvent, has a proportion of 10 wt.% to 80 wt.%, preferably 60 wt.% to 90 wt.%, in the printing composition, and the proportion of the inorganic pigments is selected accordingly, preferably 20 wt.% to 40 wt.% of the printing composition.

[0042] The second printing composition can consist of a solvent mixture and inorganic pigments. The solvent mixture preferably has a water content of 10 wt.% to 90 wt.%. The proportion of inorganic pigments in the printing composition can preferably be 20 wt.% to 40 wt.%, i.e., the solvent mixture preferably amounts to 60 wt.% to 80 wt.% of the printing composition.

[0043] The third printing composition can consist of inorganic pigments, polyacrylate as a binder, and a solvent or solvent mixture. The solvent or solvent mixture can be structured as described for the first and second printing compositions, respectively.

[0044] According to the invention, it is preferably provided that printing is carried out directly onto the concrete body, in particular directly onto a green-stable concrete body.

[0045] According to the invention, it can be provided in particular that no primer or adhesion promoter is applied to the visible surface before printing.

[0046] It has proven particularly advantageous if no primer is applied before printing. The prior art teaches that a primer or primer / adhesion promoter is applied before printing. The primer is white and enables the printing to be applied particularly well and sharply. However, the inventors have recognized that it is disadvantageous if a primer is applied to the visible surface of the concrete body, since if the visible surface or the printing is damaged, the underlying white primer becomes clearly visible, permanently destroying the appearance of the visible surface. The fact that it is preferably provided within the scope of the invention not to use a primer, but in particular to print directly onto the concrete body, in particular a green-stable concrete body, ensures that the printing composition penetrates deep into the concrete.If the visible surface is damaged, at least part of the print, or the deeper part of the print, will still be visible. Especially since the concrete itself is preferably already colored or consists of a mixture of concrete colored in different colors, the desired overall visual impression is maintained even if the visible surface is damaged.

[0047] According to the invention, it can be provided that the printing is carried out using an inkjet printing, screen printing, powder coating, laser printing, dot matrix printing, electrostatic printing, liquid printing, digital printing and / or pad printing process.

[0048] It has proven particularly suitable to use a digital printing process for printing, with the print image being transferred directly from a file, data stream, or computer to the printer. Furthermore, the use of an inkjet printing process has proven particularly suitable, as it can be carried out reliably even in the harsh environment of a stone production plant and is also cost-effective.

[0049] According to the invention, it can be provided that 5% to 90% of the visible surface of the concrete body is printed in such a way that the visible surface has a pattern through which the visible surface of the concrete body receives a natural stone look, a wood look, a textile look, a tile look or a mosaic look.

[0050] Alternatively, it can also be provided that the entire visible surface or all visible surfaces of the concrete body 1 are printed.

[0051] It has been shown that printing only 5% to 90% of the visible surface of the concrete body is particularly advantageous for giving the visible surface of the concrete body as a whole a natural stone, wood, textile, tile or mosaic look. In contrast to the teachings of the prior art, which envisage printing the entire visible surface of the concrete body, it has been shown that by printing only a portion of the visible surface, an appearance can be achieved that is closer to that of natural stone, wood, textile, tile or mosaic than by printing the entire visible surface. By printing only a portion of the visible surface, the device used for printing, in particular a printer and in particular its nozzles, is subjected to less strain. Furthermore, the consumption of ink or printing composition is reduced.

[0052] As a rule, in the case of a concrete body, for example a paving stone, only one side of the concrete body will form the visible surface when installed. In this case, it is sufficient if only one side of the concrete body, usually the top side of the concrete body, which forms the visible surface, is printed. If the concrete body is designed as a concrete step, it can be provided that the concrete body has two visible surfaces, which preferably run at an angle of 90° to one another and which are a top side and a side wall of the concrete body. In this case, both visible surfaces, i.e. the top side and the side wall, of the concrete body can preferably be printed according to the invention. However, it is also possible in this case for only one visible surface, e.g. the top side or the side wall of the concrete body, to be printed.Even when the concrete body is designed as a wall or brick, it can be provided that the concrete body has more than just one visible surface, for example two visible surfaces, which are opposite, preferably plane-parallel side walls. A concrete body designed as a brick can also have visible surfaces on the front (short) side walls and / or on the top side. It can be provided that the concrete body is printed on two, three or even four sides / walls according to the invention. However, it can also be provided that only some of the visible surfaces are printed, for example if only one side of a free-standing wall is to have a natural stone look.

[0053] It is advantageous if 5% to 80%, preferably 10% to 80%, particularly preferably 20% to 70%, in particular 30% to 70%, of the visible surface of the concrete body is printed.

[0054] The above values ​​have proven to be particularly suitable for printing on the visible surface.

[0055] According to the invention, it can further be provided that the visible surface of the concrete body is printed with at least one, preferably several crack lines, in particular crack lines with a marble look, and / or structural lines and / or notches and / or speckles and / or spots and / or shading.

[0056] It has proven particularly suitable for creating a natural stone, wood, textile, tile, or mosaic look if the visible surface is printed with crack lines, in particular crack lines with a marble look and / or structural lines, in particular of different lengths and with different gradients, and / or notches, in particular of different thicknesses and / or in different color designs. Preferably, the crack lines, structural lines, notches, speckles, spots, and shading are irregularly printed on the visible surface of the concrete body or are irregularly distributed across the visible surface.

[0057] It may be sufficient to print 10% to 20% of the visible surface with crack lines and / or structural lines and / or notches and / or speckles and / or spots to achieve a natural stone, wood, textile, tile, or mosaic look, particularly in conjunction with a visible surface that has been colored prior to printing. Please also refer to the following designs for details.

[0058] According to the invention, it can be provided that at least one area of ​​the visible surface of the concrete body, preferably the entire visible surface of the concrete body, is colored before printing.

[0059] Surprisingly, it has been shown that by coloring at least one area of ​​the visible surface of the concrete body, preferably the entire visible surface of the concrete body that is to be printed according to the invention, prior to printing, a particularly advantageous natural stone, wood, textile, tile, or mosaic appearance can be achieved without the need for full-surface printing. Coloring is preferably achieved by coloring the concrete forming the visible surface. The coloring can preferably be gray, light gray, beige, light blue, blue, green, black, white, brown, red, or yellow.Preferably, the visible surface of the concrete body is colored in such a way that it has a marble look and / or an irregular color gradient and / or an irregular structuring and / or an irregular color intensity and / or shades and / or lighter and darker areas.

[0060] It can be provided that only the visible surface or several visible surfaces of the concrete body are colored accordingly, preferably to a depth orthogonal to the visible surface of 2 mm to 30 mm. In particular, it can be provided that, in a concrete body made of core concrete and facing concrete, only the facing concrete is colored. The facing concrete generally forms the top or visible surface of the concrete body, for example, a paving stone or a concrete slab.

[0061] According to the invention, it can further be provided that the visible surface of the concrete body is given a marbling appearance and / or a structuring and / or a multi-colored design by the concrete used to produce the concrete body before printing, and / or that aggregates, in particular fine-grained aggregates, are added to the concrete.

[0062] It may be advantageous, as already explained above, if only the concrete forming the visible surface of the concrete body, for example, a facing concrete, is designed in such a way that it creates a marbled appearance and / or a textured and / or multicolored design. Alternatively or additionally, the facing concrete may also contain aggregates, particularly fine-grained aggregates made of granite or basalt.

[0063] According to the invention, it can further be provided that the method comprises the following steps: filling a colored concrete and / or a mixture of different colored concrete into a filling mold to form the concrete body, or

[0064] Pouring concrete into a filling mold to form a base body of the concrete body and pouring colored concrete and / or a mixture of differently colored concrete into the filling mold to form the visible surface of the concrete body, wherein the concrete forming the base body of the concrete body differs in color from the concrete and / or the mixture of differently colored concrete forming the visible surface of the concrete body.

[0065] It has been shown that a suitable design of the visible surface(s) of the concrete body can be achieved by pouring colored concrete and / or a mixture of different types of concrete into a filling mold for forming the concrete body. A particularly advantageous method for coloring the concrete body is known from EP 2 237 937 B1. The device and method disclosed therein allow a multicolored concrete body, in particular with a marbling appearance, to be formed in a particularly advantageous manner.

[0066] It may be provided that the entire concrete body is provided by filling a colored concrete and / or a mixture of different types of concrete into a filling mold.

[0067] Alternatively, however, it can also be provided that a conventional, in particular uncolored, concrete, in particular core concrete, is poured into a filling mold to form a base body of the concrete body, and only the area of ​​the concrete body that forms the visible surface of the concrete body is colored. Preferably, a facing concrete is used to produce the visible surface. The colored concrete and / or a mixture of different types of concrete, which forms the visible surface, or the facing concrete, is preferably filled into the filling mold in which the core concrete is already located.

[0068] The concrete that forms the base body of the concrete body differs in color from the concrete and / or the mixture of different types of concrete that form the visible surface of the concrete body, i.e. the facing concrete.

[0069] Typically, the concrete that forms the base of the concrete body, the so-called core concrete, is first poured into the filling mold and then the concrete that forms the visible surface, in particular the facing concrete, is filled in. It can be provided that after the core concrete has been poured, vibration and / or compaction, for which a stamp can be used, takes place. To produce the concrete body, however, it can also be provided that the facing concrete is first poured into the filling mold and then the core concrete is filled in to form the base of the concrete body. Furthermore, it can also be provided that the backfill concrete, then the core concrete and then the or another facing concrete is poured into the filling mold, in particular to form two visible surfaces.

[0070] After both the facing concrete and the core concrete have been poured into the filling form, regardless of the order, vibration and / or compaction takes place in the usual way.

[0071] A design of the concrete body such that it has a base body made of uncolored concrete, in particular core concrete, and only the concrete forming the visible surface(s) of the concrete body, in particular a facing concrete, is colored and / or is made from a mixture of differently colored concrete, has proven particularly advantageous because uncolored concrete, in particular core concrete, is more readily available. Despite the use of uncolored core concrete, impairments in the formation of the visible surface are not to be expected due to the fact that only the visible surface is provided by colored concrete prior to printing.

[0072] It is advantageous if the colored concrete forming the visible surface(s) and / or the mixture of differently colored concrete, in particular the facing concrete, has a thickness of at least 5 mm and preferably of at most 50 mm, particularly preferably of at most 30 mm. It is particularly advantageous if at most 30%, particularly preferably at most 20%, in particular at most 15%, of the volume of the concrete body is formed from the colored concrete and / or the mixture of differently colored concrete.

[0073] Within the scope of the invention, it can be provided that a fine-grained aggregate, for example made of granite or basalt, is added to the concrete in order to achieve a structuring or a colored appearance of the concrete.

[0074] According to the invention, it can further be provided that the concrete body is printed while the concrete body is still in a filling mold in which the concrete body is compacted, or the concrete body is printed after the concrete body has left a filling mold in which the concrete body is compacted.

[0075] It has proven particularly advantageous to print the concrete body after it has left a filling mold in which it is compacted. In this case, the concrete body is green-stable or freshly produced and already molded. However, the concrete body has not yet set or is not yet in the setting area or the setting chamber. In this state, the concrete body can be printed in a particularly suitable way, both technically and economically.

[0076] Alternatively, it is also possible to print the concrete body while it is still in a filling mold, where it is being compacted. The concrete body has already been compacted, meaning it is in a green state, but still in the production mold or filling mold. It may be particularly suitable for special applications to print the visible surface of the concrete body in this state.

[0077] One advantage here is that the printing can be carried out particularly precisely, since the position of the concrete body in the production mold or the filling mold is precisely specified.

[0078] However, it is advantageous if the printing of the visible surface takes place while the concrete body is already dimensionally stable, i.e., after completion of the main compaction process, but has not yet fully set. Preferably, the concrete body is no longer in the production mold or filling mold in which it was compacted. According to the invention, it can further be provided that the method comprises the following step: applying, preferably spraying, at least one coating, preferably made of an acrylate dispersion, to the printed visible surface of the concrete body before curing.

[0079] It has proven particularly advantageous to apply a coating to the printed visible surface of the concrete body before curing, especially before curing of the green-strength concrete body. Spraying the coating has proven particularly advantageous. It has proven particularly advantageous to use an acrylate dispersion as a coating. Surprisingly, it has been shown that a particularly good bond between the printed ink or printing composition and the concrete can be achieved if a coating, particularly an acrylate dispersion, is applied after printing but before curing.The inventor has recognized that a cement paste, which can form on the visible surface of the concrete body as a result of the compaction process during the production of the concrete body, is disadvantageous for printing and that this disadvantage can be overcome by applying a coating, in particular an acrylate dispersion, as a coating to the visible surface of the concrete body after printing.

[0080] According to the invention, it can further be provided that the method comprises the following step: applying, preferably spraying, at least one coating, preferably a UV coating, in particular a varnish, onto the printed and cured visible surface of the concrete body.

[0081] It has proven advantageous if a coating is applied, preferably sprayed, to the printed and cured visible surface of the concrete body, i.e. after the concrete body has hardened. It can also be provided that more than one coating is applied to the visible surface of the concrete body after hardening. The coating or one of the coatings can preferably be a so-called UV coating or a UV-curing coating, i.e. a coating that can be hardened by UV radiation. The coating can in particular be a varnish, in particular a UV varnish.

[0082] Within the scope of the invention, it has been found to be particularly suitable for protecting the print if, after printing but before curing, at least a first coating, preferably made of an acrylate dispersion, is applied and if, after the visible surface has cured, in particular when the concrete body has left a setting area or a setting chamber / drying room, at least one further coating, preferably a UV coating, in particular a varnish, particularly preferably a UV varnish, is applied. This makes it possible to create a particularly good and durable natural stone look, a wood look, a textile look, a tile look, or a mosaic look and to maintain this look even under harsh weather conditions, while also largely avoiding clouding. The method according to the invention can comprise further method steps in addition to the method steps already mentioned.Preferably, the concrete is compacted after being poured into the mold, in particular by vibration and / or using a stamp. Preferably, the concrete is compacted before printing. It is particularly preferred if core concrete is poured first, then preferably vibration and stamping take place, and then the facing concrete is poured, followed again by vibration and stamping or the main compaction. Within the scope of the method, preferably, the concrete body is removed from the filling mold before printing. Alternatively, printing can also take place in the mold.

[0083] It may be provided that, after printing, the concrete body is subjected to a texture-imparting surface treatment, preferably by brushing and / or embossing and / or grinding and / or shot blasting. The texture-imparting surface treatment preferably takes place after the concrete body has hardened.

[0084] The method according to the invention makes it possible to directly print concrete blanks coming from the vibrating press. The printed concrete blanks can be produced using commercially available vibrating presses and preferably pass through the printing system or printer on the production base. The product arrangement according to the mold layout can remain untouched. The concrete blanks can then be transported, preferably on the production base, to a drying chamber or drying chamber system for curing. The hydration process binds the pigments deep into the concrete, particularly the visible surface or facing layer or the concrete matrix, and creates a durable product during curing.

[0085] A preferred device for producing a printed concrete body is disclosed in claim 15.

[0086] The present invention also relates to a device for producing a printed concrete body, in particular a printed concrete block, a printed concrete slab or a printed concrete step, with a reservoir for receiving a printing composition for printing the concrete body and with a printer for printing at least one visible surface of the concrete body, wherein the printer is designed and configured to print a green-stable concrete body according to the method with a printing composition, in particular according to one of claims 1 to 14.

[0087] Any suitable printer can be used, in particular an inkjet printer or a laser printer. A digital printing process is preferably selected as the printing method. Preferably, the device according to the invention is integrated into a plant for producing a concrete body, in particular such that the device forms a station through which the concrete bodies pass after the main compaction pass, but before the setting area, in particular the setting chamber / drying chamber.

[0088] The invention also relates to a printed concrete body according to claim 16.

[0089] A particularly advantageous printed concrete body, in particular a printed concrete block, a printed concrete slab or a printed concrete step, is obtainable by the process according to the invention, in particular according to one of claims 1 to 14.

[0090] The invention further relates to a printed concrete body according to claim 17.

[0091] The present invention also relates to a printed concrete body, in particular a printed concrete block, a printed concrete slab or a printed concrete step, which has a print embedded in the concrete on at least one visible surface, wherein the print has been produced with a first printing composition, essentially consisting of color-providing inorganic pigments and a binder-free solvent, or a second printing composition, essentially consisting of color-providing inorganic pigments and a binder-free solvent mixture, or a third printing composition, essentially consisting of color-providing inorganic pigments, polyacrylate as a binder and a solvent or a solvent mixture.

[0092] According to the invention, it can be provided that only 5% to 90%, preferably 10% to 80%, more preferably 20% to 70%, particularly preferably 30% to 70% of the visible surface of the concrete body has a print and the visible surface of the concrete body has a natural stone look, a wood look, a textile look, a tile look or a mosaic look due to the print.

[0093] It has been shown that a concrete body whose visible surface is only 5% to 90% printed can be produced more cost-effectively compared to the current state of the art. On the other hand, a particularly advantageous natural stone, wood, textile, tile, or mosaic look can be achieved precisely by not completely printing the visible surface.

[0094] According to the invention, it can be provided that the printed visible surface of the concrete body has at least one coating covering the printing, preferably at least a lower coating made of an acrylate dispersion and an upper UV coating, in particular a varnish.

[0095] According to the invention, it can further be provided that printing is carried out directly on the concrete body and / or that no primer is applied to the visible surface below the printing. According to the invention, it can further be provided that at least the visible surface of the concrete body is formed by concrete that has been colored prior to printing and / or a mixture of concrete of different colors.

[0096] According to the invention, it can also be provided that the visible surface is printed with at least one, preferably several crack lines, in particular crack lines with a marble look, and / or structural lines and / or notches and / or speckles and / or spots and / or shading.

[0097] With regard to the advantages of the printed concrete body, reference is made analogously to the above statements on the method according to the invention.

[0098] Within the scope of the invention, it can be provided in particular that the printing consists exclusively of crack lines, structural lines, notches, speckles, shading and / or spots.

[0099] Features described in connection with one of the subject matters of the invention, namely the method according to the invention, the device according to the invention, and the concrete body printed with the invention, can also be advantageously implemented for the other subject matters of the invention. Likewise, advantages mentioned in connection with one of the subject matters of the invention can also be understood to apply to the other subject matters of the invention.

[0100] It should also be noted that terms such as "comprising," "having," or "with" do not exclude other features or steps. Furthermore, terms such as "a" or "the," which refer to a singular number of steps or features, do not exclude a plurality of features or steps—and vice versa.

[0101] It should be noted that terms such as "first" or "second," particularly referring to the first, second, or third printing composition, are used primarily to distinguish between the respective device or method features and are not intended to imply that features are mutually dependent or related to one another. In particular, it can be provided, for example, that the second or third printing composition can be realized within the scope of the invention without using one of the other printing compositions, e.g., the first printing composition.

[0102] The invention is described in more detail below with reference to the drawing and an embodiment.

[0103] The figures each show preferred embodiments in which individual features of the present invention are illustrated in combination with one another. Features of one embodiment can also be implemented independently of the other features of the same embodiment.

[0104] In the figures, functionally equivalent elements are provided with the same reference numerals. It shows:

[0105] Figure 1 shows a schematic cross-section through a production mold with an exemplary representation of five filling molds, in each of which a concrete body is or will be formed, wherein the concrete body has a facing concrete and a core concrete, and with a representation of stamps which can be pressed onto a concrete body from above in order to compact it and, if necessary, to structure it;

[0106] Figure 2 shows a schematic representation of a concrete body with a visible surface formed by an upper side of the concrete body, wherein a print is applied to the visible surface by means of the method according to the invention; and

[0107] Figure 3 is a schematic plan view of a visible surface of the concrete body which is printed according to the invention and which has a natural stone appearance.

[0108] The following exemplary embodiment serves to disclose an advantageous method for producing a printed concrete body 1 and to disclose an advantageous device for producing a printed concrete body 1. Furthermore, the exemplary embodiment serves to disclose an advantageous printed concrete body 1.

[0109] A printed concrete body 1 or a concrete body 1 produced according to the method or with the aid of the device is shown in principle in Figure 2.

[0110] The method according to the invention and the device according to the invention for producing a printed concrete body 1 are particularly suitable for producing a printed concrete block, in particular a paving stone, a printed concrete slab or a printed concrete step.

[0111] Accordingly, the concrete bodies 1 shown in the embodiment are preferably a concrete block, a concrete slab or a concrete step.

[0112] The method and device according to the invention provide for printing on at least one visible surface 2 of the concrete body 1. A visible surface 2 of the concrete body 1 is understood to mean, in particular, a surface / side / wall of the concrete body 1 that is visible or completely visible when the concrete body 1 is laid. Preferably, exactly one visible surface 2 of the concrete body 2 is printed using the method according to the invention.

[0113] In the exemplary embodiment, it is provided that 5% to 90%, preferably 10% to 80%, more preferably 20% to 70% and particularly preferably 30% to 70% of the visible surface 2 of the concrete body 1 is printed in such a way that the visible surface 2 has a pattern by means of which the visible surface 2 of the concrete body 1 is given a natural stone look, a wood look, a textile look, a tile look or a mosaic look.

[0114] Alternatively, it can also be provided that the entire visible surface 2 or all visible surfaces 2 of the concrete body 1 are printed.

[0115] An example of printing the visible surface 2 in such a way that the visible surface 2 has a natural stone appearance is shown in particular in Figure 3.

[0116] In the exemplary embodiment, it is provided that the visible surface 2 is printed with at least one, preferably several, crack lines 3, in particular crack lines 3 that simulate the cracks of a marble stone, and / or structural lines and / or notches 4 and / or speckles and / or spots and / or shading.

[0117] The printing with the crack lines 3 and / or the structural lines and / or the notches 4 and / or speckles and / or spots is preferably carried out in such a way that, if necessary together with other printed images, such as shading, only the aforementioned percentage of the visible surface 2 of the concrete body 1 is printed.

[0118] After printing the visible surface 2, the concrete body 1 is intended to harden. For hardening, the concrete body 1 can preferably be placed in a curing or setting area, in particular a drying chamber.

[0119] In the exemplary embodiment, the visible surface 2 represents an upper side 1a of the concrete body 1. The concrete body 1 is preferably cuboid-shaped and further comprises a lower side 1b and side walls 1c extending orthogonally thereto.

[0120] It should be noted that the visible surface 2 can also represent a bottom side 1b or one of the side walls 1c. Furthermore, it can be provided that several of the sides / walls 1a, 1b, 1c of the concrete body 1 are designed as visible surfaces 2 and printed using the method according to the invention.

[0121] In the exemplary embodiment, it is provided that at least one area of ​​the visible surface 2 of the concrete body 1, in the exemplary embodiment the entire visible surface 2 of the concrete body 1, is colored before printing.

[0122] The natural color of the concrete used to produce the concrete body 1 is gray. In the exemplary embodiment, it is preferably provided that at least the concrete forming the visible surface 2 of the concrete body 1 is colored prior to printing in such a way that the color of the concrete deviates from the natural color, possibly only by selecting a different shade of gray, and / or by shaping the concrete to create a marbling effect, and / or by adding fine-grained aggregates, for example, made of granite or basalt, to the concrete. The concrete can also be structured and / or multicolored.

[0123] In the exemplary embodiment, it can be provided that, in order to produce the concrete body 1, colored concrete and / or a mixture of differently colored concrete is poured into a filling mold 5 for shaping the concrete body 1. A filling mold 5 for shaping a concrete body 1 is shown in principle in Figure 1. Figure 1 shows a production mold 6 for producing a layer of concrete bodies 1. In the exemplary embodiment, the production mold 6 has five filling molds 5 in order to form a corresponding number of concrete bodies 1. In the exemplary embodiment, it is provided that after the concrete has been poured into the filling mold 5, vibration and compaction take place, preferably using a stamp 7.

[0124] Figure 1 shows a particularly advantageous method for producing the concrete body 1. It is provided that first, a so-called core concrete is poured into the filling mold 5 to form a base body 8 of the concrete body 1. The core concrete used to produce the base body 8 is preferably not colored. After the core concrete has been poured, in the embodiment according to Figure 1, a colored concrete and / or a mixture of differently colored concrete is poured into the filling mold 5 to form the visible surface 2 of the concrete body 1. This is preferably a so-called facing concrete, which is generally less coarse than the core concrete. The concrete that forms the visible surface 2 of the concrete body 1, or the facing concrete, differs in color from the core concrete in that the facing concrete is colored and / or is formed from a mixture of differently colored concrete.

[0125] The facing concrete, or the concrete that forms the visible surface 2, is referred to in the exemplary embodiment as the facing layer 9. The base body 8 and the facing layer 9 together form the concrete body 1.

[0126] To produce a mixture of concrete of different colours, a colouring method as described in EP 2 237 937 B1 is preferably used within the scope of the invention.

[0127] As shown in principle in Figure 1 and Figure 2, it is preferably provided that the concrete body 1 is formed essentially from the base body 8 or the core concrete, preferably at least 80%, and the concrete which forms the visible surface 2, ie the facing layer 9 made of the facing concrete, makes up at most 20% of the volume of the concrete body 1.

[0128] To produce the concrete body 1, it is preferably provided that the core concrete is first poured into the filling mold 5. This is preferably followed by vibration and / or intermediate compaction, preferably with the aid of the stamp 7. The facing concrete is then filled into the filling mold 5 to form the facing layer 9. This is preferably followed by vibration and compaction again, in particular with the aid of the stamp 7. Vibration units placed beneath the production mold are preferably used for the vibration. After the facing concrete has been poured, the main compaction preferably takes place. It can be provided that structuring is introduced into the visible surface 2 of the concrete body 1 with the aid of the stamp 7. It can also be provided that a chamfer is introduced all the way around the edge of the visible surface 2. The concrete body 1 is then removed from the filling mold 5 or the formwork is demolded.

[0129] The order of filling the core concrete and the facing concrete can also be reversed, ie, the facing concrete is poured into the filling form 5 first. Furthermore, facing concrete can be poured either before or after the core concrete.

[0130] The concrete body 1 can be printed while the concrete body 1 is still in the filling mold 5 in which the concrete body 1 is compacted. However, it is advantageous if the concrete body 1 is printed after the concrete body has left the filling mold 5 in which the concrete body 1 is compacted.

[0131] In the exemplary embodiment, it can be provided, in a manner not shown, that a coating is applied after printing on the visible surface of the concrete body, but before curing. The coating is preferably a coating made of an acrylate dispersion. The coating is preferably sprayed on. A rolling or curtain coating process may also be suitable for applying the coating.

[0132] In the exemplary embodiment, it can be provided (not shown) that after curing, i.e., a coating is applied, preferably again sprayed, to the printed and cured visible surface 2 of the concrete body 1. This is preferably a coating that cures with the aid of UV radiation or is self-curing.

[0133] It can also be provided that more than one coating, for example two coatings, are applied to the printed and cured visible surface 2 of the concrete body 1, of which preferably one coating is a UV coating, preferably a UV varnish.

[0134] It has proven particularly suitable if, after printing but before curing, a coating of acrylate dispersion is applied to the visible surface 2 of the concrete body 1 and then, when the concrete body 1 has cured, at least one further coating, in particular a UV coating, is applied to the cured visible surface 2 of the concrete body 2.

[0135] In the exemplary embodiment, it is provided that the printing of the visible surface 2 of the concrete body 1, in particular a green-stable concrete body 1, is carried out with a printing composition 10, essentially consisting of color-imparting inorganic pigments and a preferably binder-free solvent (first printing composition) or a preferably binder-free solvent mixture (second printing composition). Figure 2 shows a reservoir 11 for holding the printing composition 10 only schematically. Furthermore, Figure 2, likewise only schematically, shows a printer 12, in the exemplary embodiment preferably an inkjet printer, with which the printing of the visible surface 2 of the concrete body 1 is carried out. In this case, printing is preferably carried out directly on the visible surface 2 of the concrete body 1, i.e. directly on the concrete, in particular the facing layer 9.

[0136] In the exemplary embodiment, as an alternative to printing with the first or the second printing composition 10, printing with a third printing composition 10 can also be provided, which essentially consists of color-imparting inorganic pigments, polyacrylate as a binder and a solvent or a solvent mixture.

[0137] In the first printing composition 10, it is preferably provided that the solvent contains no siloxane, no silane, and no resin, i.e., it is siloxane-free, silane-free, and resin-free. The coloring pigments are preferably UV-resistant. Furthermore, in the first printing composition, it is provided that the solvent contains no water content or is not an aqueous system. In the first printing composition, the printing composition 10 can preferably consist of 10% to 90% by weight of the solvent and a corresponding percentage by weight of the coloring pigments, as well as any unavoidable residual impurities.

[0138] In the second printing composition 10, it is preferably provided that the solvent mixture contains no siloxane, no silane, and no resin, i.e., the solvent mixture is siloxane-free, silane-free, and resin-free. In the second printing composition 10, it is preferably provided that the coloring pigments are UV-resistant. Furthermore, in the second printing composition, it is provided that the solvent mixture has a water content of 10 wt.% to 90 wt.%. In the context of the printing composition 10, it can be provided that the coloring inorganic pigments make up 20 wt.% to 40 wt.%, i.e., the printing composition 10 consists of 20 wt.% to 40 wt.% of the coloring pigments, and the solvent mixture has a corresponding percentage by weight, so that the printing composition 10 is formed from these two components. In the context of the solvent mixture, it can be provided that the water content is 10 wt.-% to 90 wt.%, preferably 30 wt.% to 60 wt.%.

[0139] Within the scope of the third printing composition 10, in which polyacrylate is used as a binder within the scope of the printing composition 10, a solvent or a solvent mixture can be used, which can be selected as described for the first printing composition and the second printing composition 10. In the third printing composition, it can be provided that the printing composition 10 consists of 20 wt.% to 40 wt.% of the color-imparting, inorganic pigments.

[0140] Within the scope of the method according to the invention, it is preferably provided that printing takes place directly onto the visible surface 2 of the concrete body 1. Within the scope of the method according to the invention, it is particularly provided that no primer is applied to the visible surface 2 before printing, ie, the visible surface 2 is primer-free.

[0141] In the exemplary embodiment (not shown), it can be provided that the visible surface 2 is subjected to a structure-imparting surface treatment after printing, preferably by brushing, embossing, tapping or striking, in particular by shot blasting, as described in EP 1 893 391 B1.

Claims

Patent claims 1. A method for producing a printed concrete body (1), in particular a printed concrete block, a printed concrete slab or a printed concrete step, comprising at least the following steps: Printing on at least one visible surface (2) of the concrete body (1), wherein the printing on the concrete body (1) is carried out in a green state of the concrete body (1), in which the concrete body (1) is dimensionally stable but not yet hardened, and hardening of the concrete body (1) after printing, characterized in that a) the printing is carried out with a first printing composition (10), essentially consisting of color-providing inorganic pigments and a binder-free solvent, or b) the printing is carried out with a second printing composition (10), essentially consisting of color-providing inorganic pigments and a binder-free solvent mixture, or c) the printing is carried out with a third printing composition (10), essentially consisting of color-providing inorganic pigments, polyacrylate as a binder and a solvent or a solvent mixture.

2. The method according to claim 1, characterized in that a) the solvent is siloxane-free and / or silane-free and / or resin-free, and / or b) the coloring pigments are UV-resistant, and / or c) the solvent has no water content or is not an aqueous system, and / or d) the printing composition (10) consists of 10 wt.% to 90 wt.% of the solvent and the coloring pigments.

3. Process according to claim 1, characterized in that a) the solvent mixture is siloxane-free and / or silane-free and / or resin-free, and / or b) the coloring pigments are UV-resistant, and / or c) the solvent mixture has a water content of 10% by weight to 90% by weight.

4. Method according to claim 1, 2 or 3, characterized in that the concrete body (1) is printed directly onto the concrete forming the visible surface (2).

5. Method according to one of claims 1 to 4, characterized in that no coating and / or primer is applied to the visible surface (2) prior to printing. Method according to one of claims 1 to 5, characterized in that the printing is carried out using an inkjet printing, screen printing, powder coating, laser printing, needle printing, electrostatic printing, liquid printing, digital printing and / or pad printing process. Method according to one of claims 1 to 6, characterized in that 5% to 90% of the visible surface (2) of the concrete body (1) is printed in such a way that the visible surface (2) has a pattern through which the visible surface (2) of the concrete body (1) acquires a natural stone appearance, a wood appearance, a textile appearance, a tile appearance or a mosaic appearance. Method according to claim 7, characterized in that 10% to 80%, preferably 20% to 70%, particularly preferably 30% to 70% of the visible area (2) of the concrete body (1). Method according to one of claims 1 to 8, characterized in that the visible surface (2) of the concrete body (1) is provided with at least one, preferably several crack lines (3), in particular crack lines (3) with a marble look, and / or structural lines and / or notches (4) and / or speckles and / or spots and / or shades are printed. Method according to one of claims 1 to 9, characterized in that the visible surface (2) of the concrete body (1) is given a marbling appearance and / or a structuring and / or a multi-colored design by the concrete used to produce the concrete body (1) before printing, and / or a color and / or additives, in particular fine-grained additives, are added to the concrete used to produce the concrete body (1) before printing. Method according to one of claims 1 to 10, comprising the following step: Pouring a coloured concrete and / or a mixture of different coloured concrete into a filling mould (5) to form the concrete body (1), or Pouring concrete into a filling mould (5) to form a base body (8) of the concrete body (1) and pouring a coloured concrete and / or a mixture of different coloured concrete into the filling mould (5) to form the visible surface (2) of the Concrete body (1), wherein the concrete forming the base body (8) of the concrete body (1) differs in color from the concrete and / or the mixture of differently colored concrete forming the visible surface (2) of the concrete body (1).

12. Method according to one of claims 1 to 11, characterized in that the concrete body (1) is printed while the concrete body (1) is still in a filling mold (5) in which the concrete body (1) is compacted, or the concrete body (1) is printed after the concrete body (1) has left a filling mold (5) in which the concrete body (1) is compacted.

13. Method according to one of claims 1 to 12, comprising the following step: Applying, preferably spraying, at least one coating, preferably made of an acrylate dispersion, to the printed visible surface (2) of the concrete body (1) before curing.

14. A method according to any one of claims 1 to 13, comprising the following step: Applying, preferably spraying, at least one coating, preferably a UV coating, in particular a varnish, onto the printed and cured visible surface (2) of the concrete body (1).

15. Device for producing a printed concrete body (1), in particular a printed concrete block, a printed concrete slab or a printed concrete step, with a reservoir (11) for receiving a printing composition (10) for printing the concrete body (1) and with a printer (12) for printing at least one visible surface (2) of the concrete body (1), wherein the printer (12) is designed and configured to print a green-stable concrete body (1) according to the method with a printing composition according to one of claims 1 to 14.

16. Printed concrete body (1), in particular printed concrete block, printed concrete slab or printed concrete step, obtainable by a process according to one of claims 1 to 14.

17. A printed concrete body (1), in particular a printed concrete block, printed concrete slab or printed concrete step, which has a print embedded in the concrete on at least one visible surface (2), wherein the print has been produced with a. a first printing composition (10), essentially consisting of color-providing inorganic pigments and a binder-free solvent, or b. a second printing composition (10), essentially consisting of color-providing inorganic pigments and a binder-free solvent mixture, or c. a third printing composition (10), essentially consisting of color-imparting inorganic pigments, polyacrylate as a binder and a solvent or a solvent mixture.

18. Printed concrete body according to claim 17, characterized in that only 5% to 90%, preferably 10% to 80%, more preferably 20% to 70%, particularly preferably 30% to 70% of the visible surface of the concrete body (1) has a print and the visible surface of the concrete body (1) has a natural stone look, a wood look, a textile look, a tile look or a mosaic look due to the print.

19. Printed concrete body (1) according to claim 17 or 18, characterized in that the printed visible surface (2) of the concrete body (1) has at least one coating covering the printing, preferably at least a lower coating made of an acrylate dispersion and an upper UV coating, in particular a UV varnish.

20. Printed concrete body according to claim 17, 18 or 19, characterized in that the concrete body (1) is printed directly onto the concrete forming the visible surface (2) and / or no primer is applied to the visible surface (2) below the printing.

21. Printed concrete body according to one of claims 17 to 20, characterized in that at least the visible surface (2) of the concrete body (1) is formed by a concrete colored before printing and / or a mixture of different colored concrete.

22. Printed concrete body according to one of claims 17 to 21, characterized in that the visible surface is printed with at least one, preferably several crack lines (3), in particular crack lines (3) with a marble look, and / or structural lines and / or notches (4) and / or speckles and / or spots and / or shading.

Images