Coated fiber cement product and method of manufacturing thereof

Abstract

The coated fiber cement product (100) is provided with a print (32) and comprises a substrate (10) of autoclave-cured fiber cement material, a coating system (20) applied on a first main surface (11) and side edges (13) of the substrate, wherein the coating system comprises a primer (21) and a colored coating (22). The product (100) further comprising a printing system (30) on the main surface (11) of the substrate (10), which printing system (30) comprises a first UV-cured transparent coating (31), the print (32) and a second UV-cured transparent coating (33).

Description

[0001] Coated fiber cement product and method of manufacturing thereof.

[0002] FIELD OFTHE INVENTION

[0003] The invention relates to a fiber cement product provided with a print, comprising:

[0004] a substrate of cured fiber cement material, which substrate is provided with a first and second opposed main surfaces;

[0005] A primer applied on at least said first main surface;

[0006] A print on top of the first UV-cured transparent coating, said print comprising a printed pattern of ink, and

[0007] A UV-cured transparent coating on top of said print.

[0008] The invention further relates to a method of manufacturing such a fiber cement product provided with a print.

[0009] BACKGROUND OFTHE INVENTION

[0010] Such a method and such a fiber cement product are known from WO2016 / 146423A1. As specified in said patent application, it is difficult to apply printing on a substrate of cured fiber cement material, since such substrates have a high degree of heterogeneity and surface roughness, which would inevitably cause ink bleeding. The high degree of heterogeneity is due to the combination of fibers and cement or cementitious material. The solution proposed in said patent application is the provision of a primer layerwith a pigment volume concentration of at least 40%, and preferably higher. Therewith the porosity of the primer layer becomes higher than the porosity of the underlying substrate of fiber cement material. This allows to apply a printed pattern on top of the primer, especially by means of inkjet printing of a solvent based ink that is dried after its application.

[0011] In practice, such inkjet printed products of fiber cement are sold for interior applications. This is reflected in the PVC of the coating. The exemplary primer layer in said patent application had a PVC of about 62%. With this value, it is above the critical pigment volume concentration, which is defined as 1 / (1 + (OA)(p) / 93.5), wherein OA is the oil absorption number and p is the pigment density. ForTiO2, the OA is 20 and p is 4.2, leading to a critical PVC of 52.7%. Above this critical pigment volume concentration, the film density decreases and air voids may be present. Such coating with air voids may be good for absorbing the oil-based printing ink, but it will be weak when exposed to exterior applications.

[0012] SUMMARY OF THE INVENTION

[0013] It is therefore an object of the present invention to provide a fiber cement product with a print on this first main surface that configured for use in exterior applications.

[0014] It is a further object of the invention to provide a method of manufacturing thereof. According to the invention, the first object is achieved in a coated fiber cement product provided with a print, comprising: (1 ) a substrate of autoclave-cured fiber cement material, which substrate is provided with a first and second opposed main surfaces and side edges extending between said main surfaces; (2) a coating system applied on at least said first main surface and said side edges, wherein the coating system comprises a primer and a coloredcoating; (3) a first UV-cured transparent coating on said coating system, which first UV-cured transparent coating is present on the first main surface; (4) a print on top of the first UV-cured transparent coating, said print comprising a printed pattern of ink, and (5) a second UV-cured transparent coating on top of said print.

[0015] The further object is achieved in a method of manufacturing a coated fiber cement product comprising the steps of:

[0016] Providing a substrate of autoclave-cured fiber cement material, which substrate is provided with a first and second opposed main surfaces and side edges extending between said main surfaces;

[0017] Applying a coating system on at least said first main surface and said side edges of said substrate, wherein applying the coating system comprises applying a primer onto said surfaces of the substrate and applying a colored coating onto the primer;

[0018] Applying a first UV-curable transparent coating on said coating system, which first transparent UV-curable coating is present on the first main surface, and curing said UV-curable transparent coating by UV-radiation;

[0019] Providing a printed pattern of ink on top of the first UV-cured transparent coating, Applying a second UV-curable transparent coating covering said print and said first UV-cured transparent coating, and curing said second UV-curable transparent coating.

[0020] It has been found in investigations leading to the invention, that products configured for exterior use may be produced from an autoclave-cured substrate of fiber cement material, which is first coated with a coating system so as to cover not only the main surface but also side edges of the substrate. This coating system comprises a double coating of a primer layer and a coating layer. This coating system is then covered with a UV-curable transparent coating on its main surface, which is UV cured prior to application of the printing ink. Tests indicated that with removal of one or more of the layers below the print led to insufficient durability, either due to lacking adhesion and / or due to dimensional stability of the product. The use of an autoclave-cured substrate prevents occurrence of efflorescence and potential fragility of the coating system due to outflow of alkaline liquid from the fiber cement substrate.

[0021] In an advantageous embodiment, the wherein the substrate of fiber cement material has a density of at least 1.2 kg / dm3 and less than 1.5 kg / dm3 and wherein said first main surface is a textured surface. This product of this embodiment turns out to have beneficial visual appearance, wherein the print enhances the three-dimensional effect of the textured surface. It is believed by the inventors, that the said enhancement of three-dimensional effect is partly due to the presence of the first and second UV-cured transparent coatings. This may give rise to light refraction at locations where the substrate is not planar. A substrate of fiber cement material with a textured surface is preferably a substrate that has not been compressed after its initial manufacture and prior to the curing thereof. Such substrates have a density of less than 1.5 kg / dm3. If a compression step were carried out, any pre-defined shape modifications would be distorted, and hence, any texture should be applied after compression and especially curing. At that stage, the substrate is hardened, rendering texturing more difficult. A too low density is undesired for use in exterior applications.

[0022] Modifying the shape of a not yet cured fiber cement substrate may be performed in severalways, such embossing (also known as press moulding), bending, thinning. In a preferred manner, the textured shape is produced in that an accumulator roll used in the manufacture ofthe substrate in accordance with the Hatschek or flow-on process, is provided with - a negative of -said texture pattern. Therewith, said textured shape is provided in a phase when the fiber cement material is still comparatively wet. It therewith avoids local variations in density and damages to the substrate, and provides desired texture in a reproducible manner. The texture pattern preferably comprises both protrusions and depressions, and more preferably such protrusions and depressions have a length longerthan theirwidth and are especially channels and ridges. In the resulting product, such channels and ridges may also be referred to as valleys and hills. A height variation between a channel and a ridge is advantageously at least 100 pm, more preferably at least 200 pm, and may well be larger to above 1 mm.

[0023] In a further embodiment, the porosity of the substrate of fiber cement material is between 30% and 45%. This is deemed useful for adhesion of the primer. Porosity herein has been measured as the difference of the saturated weight and the dry weight, divided by dry weight and multiplied with 100%. The dry weight herein is measured after 48 hours drying at 105°C. The saturated weight is the weight measured after 72 hours saturation in tap water at ambient, laboratory temperature.

[0024] The primer of the coating system is preferably a pigmented primer. More preferably, said pigmented primer has a color corresponding to the color of the colored coating of the coating system. Therewith, the coating system provides a colored, opaque background to which the print can be designed to be an add-on and supplementary to achieve a desired design. A colored primer is typically iron oxide based, which may contribute to adhesion to the surface of the fiber cement substrate. It is preferred that the primer extends on all sides of the substrate of fiber cement material, so as to form an encapsulation. This improves the protection of the fiber cement substrate. Even though the second main face is not exposed to exterior weather during its use, the second main face may be arranged in a ventilation channel and therewith be exposed to humidity. The coating is preferably applied as an aqueous emulsion.

[0025] The colored coating of the coating system may be a colored coating that is thermally cured or dried for coalescence. Use of a radiation-curable coating is not desired, as any UV-radiation would not cure the coating due to the presence of the pigment. The colored coating is a conformal coating, so that the texture of the surface remains. It is suitably applied as an aqueous dispersion, also a solvent-based system is not excluded. Suitable binders are for instance polyacrylates and polyurethanes. Very good results were obtained when using a thermally curable, 2-component (2K) polyurethane coating.

[0026] It is an advantage of the process and product of the invention, that the PVC of the layers in the coating system is reduced relative to the prior art. The coating layers thus comprise less pigment relative to the amount of binder, typically resulting in lower cost and different coating behaviour. In fact, the PVC of the layers is preferably lower than the critical pigment volume concentration, implying that there is more binder than needed to provide a completely absorbed layer on the pigment surface as well as to fill the interstitial spaces between the pigment particles in a close-packed system. Preferably, the PVC of the primer layer is at most 15%, by further preference at most 10%. The PVC of the coating layer is preferably at most 30%, for instance in the range of 15-25%.

[0027] Another advantage resides therein that the coating system is applied in a conformal manner. This conformal deposition results in coating thicknesses, wherein a coating thickness on top of a ridge is at least 50% of a coating thickness on top of a depression, and preferably at least 60% thereof.In again a further embodiment, the coating system is applied on the side edge with a larger thickness as on the main surface of the substrate of fiber cement material. This is arranged to obtain a higher degree of protection against ingress of humidity and / or dust via side edges. It is especially relevant in case that the second coating of the coating system is a thermoplast, i.e. a coating with coalescence due to drying rather than by means of thermal or UV curing. The thickness on the side edge is for instance between 120% and 200% of a coating thickness on a main surface, wherein said coating thickness on a main surface is defined as a coating thickness on a ridge or hill thereof.

[0028] The transparent UV-curable coatings are known per se. Polyurethane acrylates are deemed preferred as being very weathering-resistant. The first UV-curable coating may well bond to the underlying coloured coating, which is beneficial for strength. A pigment or a filler may be present in the transparent UV-curable coating. Preferably, the said at least one transparent coating has a pigment volume concentration in the range of 0.01 to 3%, wherein the pigment volume concentration can be calculated via the following mathematical formula: " pigment volume concentration " expressed in % = " PVC " expressed in % = volume of pigments + volume of fillers / (volume of pigments + volume of fillers + volume of solid binder(s)) * 100 expressed in %. Use of a nanoscale pigment is deemed advantageous. Such nanoscale pigment may further contribute to increase UV-resistance. A preferred nanoscale pigment is nanoscale TiO2. Such nanoscale pigments are also known as transparent pigments, as they do not scatter radiation.

[0029] In one implementation, the transparent UV-curable coatings are applied at a thickness of 5-20 g / m2and more preferably 6-15 g / m2or even 7-12 g / m2, as based on dry thickness. This is a comparatively thin thickness, which may well contribute to the resultingvisual effect. The first UV-curable coating is preferably thinner than the second UV-curable coating. In addition to the second UV-curable coating, a third UV-curable coating may be present, which then overlies the second UV-curable coating. Preferably, the total thickness of the UV-cured coatings, after deposition and curing is at most 20 pm.

[0030] The ink used for the printing is preferably non-UV curable. It is to be dried after its application in the form of an aqueous or solvent dispersion. Preferably, use is made of inorganic pigments, although organic colorants are not excluded.

[0031] In a further embodiment, the product further comprises an intermediate transparent coating covering the print and a second print comprising a printed pattern of ink on top of said intermediate transparent coating, wherein said second UV-cured transparent coating covers said second print. In this further embodiment, the product is provided with a first and a second printed pattern, mutually separated via an intermediate transparent coating. Such intermediate transparent coating preferably is a UV-curable coating, butthat is not deemed strictly necessary. In this manner, two different prints can be provided in an overlying manner without getting merged.

[0032] It is observed for clarity that any of the embodiments and implementation discussed hereabove are applicable to all aspects of the invention, even if not mentioned so explicitly.BRIEF INTRODUCTION OFTHE FIGURES

[0033] These and other aspects of the invention, will be further elucidated with reference to the figures, which are not drawn to scale and purely diagrammatical in nature, wherein:

[0034] Fig. 1 shows in a diagrammatical, cross-sectionalviewthe coated fiber cement product of the invention.

[0035] DETAILED DISCUSSION OF ILLUSTRATED EMBODIMENTS

[0036] Fig. 1 shows in a diagrammatical and cross-sectional view a first embodiment of the product 100 of the present invention. The figure is not drawn to scale. In fact, in reality, the layer thickness of the coating system 20 and the printing system 30 is much smaller in comparison to the thickness of the substrate 10 than shown in Fig. 1. Furthermore, the layer thicknesses of the individual coating and printing layers 21 , 22, 31 , 32, 33 is not drawn to scale. While the figure suggests that the texture 14, 15 on the main surface 11 of the substrate 10 issmoothened out due to the coating and printing layers on top thereof, this is in reality not the case. The product 100 comprises a substrate 10 of fiber cement material. The substrate 10 is provided with a first, main surface 11 , a second rear surface 12 opposed from the first surface 11 and side edges 13. Typically, the substrate 10 has a thickness in the range of 8-15 mm, such as 10-12 mm. Its length may be 2-4 meters and its width may be from 0.3 m to 1.5 m. The main surface 11 of the substrate 10 is textured, in that grooves 14 and ridges 15 are provided in accordance with a desired pattern. The substrate 10 is coated with a coating system 20, comprising a primer coating 21 and a colored coating 22. A printing system is applied on the first main surface 11 of the substrate 10 on top of the coating system 20. This printing system comprises a first transparent coating 31 , a print 32 and a second transparent coating 33. A third transparent coating may be present on top of the second transparent coating. Said third transparent coating is preferably UV-cured.

[0037] Manufacture of the product 100 starts with manufacture of the substrate 10 of fiber cement material. Thereto, a fiber cement composition is prepared, which has the form of an aqueous slurry. Fiber cement compositions at least comprise organic fibers and cement. In case of substrates that are to be cured by means of an autoclave treatment, the fiber cement composition further comprises silica, especially in the form of quartz. Fly ash may be a supplementary source of silica. A source of aluminium is typically added in fiber cement compositions for autoclave-curing, for instance up to 5% by weight, based on dry weight of the composition. Typical sources of aluminium are kaolin and aluminumtrihydrate (ATH), although other sources, for instance in the form of recycled material with a suitable composition are not excluded.

[0038] Autoclave-curing is essentially steam curing of the cement at temperatures above 100°C, and even beyond 150°C and typically a higher pressure. In order to prevent formation of porous and weak phases (crystalline alpha dicalcium silicate hydrate (a-C2SH) and C3SH1.5) silica (SiO2) is added to the composition. The amount of cement typically is in the range of 25-55 weight% based on dry weight of the composition. The silica content is typically in the range of 20-45 weight% based on dry weight of the composition. This results in formation of more complex and crystalline calcium silicate hydrates (CSHs) during autoclave-curing, and particularly tobermorite, a calcium silicate hydrate existingwith chemical formulas Ca5Si6O16(OH)2-4H2O and Ca5Si6(O,OH)18-5H2O. The amount of tobermorite and otherCSHs formed duringthe autoclaving is for instance dependent on the initial composition and the autoclave curing conditions.

[0039] The fibers used in fiber cement compositions for autoclave-curing need to withstand temperature and pressure of the autoclave-curing. Most synthetic fibers are not feasible of doing so, therefore the primary fiber for such compositions is cellulose. Aramide fibers may be used additionally. The amount of cellulose fibers used in such fiber cement compositions is typically from 5 to 10% by weight, based on dry weight of the composition, in case that cellulose fibers are the only fibers.

[0040] The fiber cement composition comprises water to such extent that an aqueous slurry of particles is formed, of which individual particles may be picked up to form thin layers which are then transported over a felt to an accumulator roller on which the thin layers are stacked to form a sheet of a desired thickness. Once that sufficient layers are stacked, the sheet on the accumulator roll is cut, resulting in a sheet of uncured, thus green sheet of fiber cement material. In a preferred implementation according to the present invention, the accumulator roll is provided with a plurality of protrusions in accordance with a pattern. The said pattern is a negative of texture to be arranged in a main surface of the resulting sheet of fiber cement material. The accumulator roll may further be provided with grooves or depressions, in case some ridges or protrusions on the main surface are desired. This seems preferable to obtain a pattern corresponding to a wood structure.

[0041] The preferred process for forming green sheets is the Hatschek process. Alternative processes include the Magnani process and the flow-on process. In again a further alternative, a combination of a flow-on and a Hatschek process may be used, so as to generate a sandwich panel, as known per se from WO2019 / 068829A1. The Hatschek process at least comprises the steps of: (i) building a fiber cement film on a sieve, which sieve rotates so as to be in contact with a fiber cement slurry in a vat; (ii) transferring the fiber cement film from the sieve to the felt transport belt, and (iii) accumulating the fiber cement film on an accumulator roll via the felt transport belt. As is known, a single machine for performing the Hatschek process may comprise more than one sieve. The fiber cement film processed on the Hatschek machine typically has a thickness of between about 0.01 mm and about 0.9 mm, such as in particular between about 0.05 mm and about 0.5 mm, such as between about 0.1 mm and about 0.4 mm, such as about 0.3 mm. The fiber cement film is de-watered in the course of the Hatschek process, resulting in decrease of thickness but better consistency.

[0042] After formation, the green sheet may further be treated to create further indentations, for instance by means of embossing. A compression step is not applied in accordance with the a preferred embodiment of the invention, so as not to damage the created texture in and / or on the main surface.

[0043] Subsequent thereto, the green fiber cement sheet is cured. A precuring step is preferably carried out, by exposing the green fiber sheet to air. The pre-curing step may take several hours, e.g. between about 1 hour and 10 hours, such as between 2 hours and 8 hours, such as between 3 hours and 5 hours, preferably about 4 hours, during which the temperature of the sheets rise due to the exothermic curing reaction of the cement. The pre-curing may take place in controlled conditions controlling the humidity, temperature or both. Duringthe precuring, some of the phases of the cement, such as portlandite, will react with humidity. This brings the cement in a better state for performing the subsequent reaction duringthe autoclavetreatment. The thickness of the resulting sheet is in the range of 6-15 mm, preferably 8-12 mm.The resulting autoclave-cured fiber cement sheet is then cut into desired dimensions, resulting in a substrate of autoclave-cured fiber cement material. The present printing technology has been developed for plank-shaped substrates, with a length in the range of 2 to 4 meter and a width of 0.10 to 0.60 meter, such as a length between 3.5 and 4 meters and a width between 0.10 and 0.40 meter. The side edge herein includes an angle of approximately 90 degrees relative to the main surface. Approximately 90 degrees is herein between 85 and 95 degrees. However, the angle between the main surface and the side edge may be different herefrom, and for instance be in the range of 90 to 150 degrees. In such an implementation, a further side edge may be present between the -first -side edge and the second, rear surface. Side edge angles may further be complementary, in the sense that from opposed side edges of one substrate the first includes an angle with the main surface that exceeds 90 degrees and the other includes an angle with the main surface that is smaller than 90 degrees, wherein the difference to 90 degrees is preferably equal or equal within a margin of tolerance of for instance 5 degrees.

[0044] This material is then first coated with a coating system, following by the provision of a print as part of a printing system. A first layer of the coating system is a primer coating, which is in the present example an acrylate-based pigmented primer which is applied as an emulsion and subsequently dried. The said first layer is applied on all sides of the substrate by means of any suitable application technology, such as spraying, rolling and the like. Use of a roller seems preferred. The PVC of the coating is preferably less than 15 or even less than 10. The dry layer thickness is in the range of 10-20 pm, for instance in the range of 13-18 pm. The second layer of the coating system is a colored coating and is applied in a dry layer thickness in the range of 30-100pm, for instance 40-70 pm. If the second layer were too thick, the texture of the surface might be reduced. Good results have been obtained both with a colored acrylate-based coating and a 2K PUR (polyurethane) coating, to be cured by a thermal treatment. The PVC is preferably in the range of 15-25%, for instance 16-20%. The colored coating is deposited both on the main surface as well as on the side edges of the substrate. Application processes include spraying, spattering, rolling, curtain-spraying and the like as known to the skilled person. Preferably, the resulting coating is conformal, in the sense that texture on the main surface is still present after coating, rather than being flattened out.

[0045] Afterwards, a printing system is applied, comprisingthe application of a print by means of inkjet printing, in between of a first and a second transparent UV-curable layer, wherein said UV-curable layers are cured immediately after their application and drying. The first and second UV curable layers are preferably based on a polyurethane acrylate material, and further include a photoinitiator. Examples of suitable UV-curable layers are for instance known from EP1914215B1. They may be applied in a suitable thickness, for instance in the range of 5-20 g / m2, such as 10-15 g / m2.The printing ink is solvent-based and is preferably applied in minor quantities with negligible dry layer thickness. It is not excluded that a further transparent coating is applied on top of the second transparent coating, to provide additional protection.

[0046] EXAMPLES

[0047] Coating and printing tests were performed on medium density substrates of fiber cement material manufactured in or for Eternit BV, Kapelle-op-den-Bos, Belgium. The medium density substrates were autoclave-cured and had a density of 1.3 kg / dm3and a thickness of 12 mm.They were cut into planks with a length of 3.6 m and a width of 19 cm. On a main surface of the substrate, texture was present in the form of a wood nerve profile defined into the main surface as grooves and indentations.

[0048] The substrates of fiber cement material were subjected to different coating sequences followed by printing and a final UV curing step. The coating process prior to the inkjet printing is shown in Table 1.

[0049]

[0050] Table 1 - coating processes

[0051] The UV primer is acrylate based. It is applied in an amount of 40-50 g / m2. Primer 1 is an aqueous acrylic emulsion primer with PVC of less than 10%. It is applied in an amount of 10-30 g / m2. Coating 1 is an aqueous acrylic emulsion paint with PVC in the range of 15-20%. It is applied in an amount of 80-100 g / m2. Coating 2 is a two-component polyurethane thermally curable coating. It is applied in an amount of 200-220 g / m2. The UV-curable coating is a polyurethane acrylate coating. It is applied in an amount of 8 g / m2below the print, and two coating layers of each 12 g / m2above the print. All values herein are based on dry thicknesses.

[0052] Performance of the different samples were tested by means of a tape test applied to coated and printed products after 0, 50 and 100 thawing / freezing cycles, in accordance with EN 12467 with freezing at -20°C for 2 to 3 hours and thawing by submerging in water of 20°C for 2 to 3 hours. For some of the samples, furthermore the tape test was done after 14 cycles of heat rain. The heat rain test is applied on a panel of fastened 8 substrates. In each cycle, heat of 60°C is applied during 15 hours and 50 minutes. Following 10 minutes of break / rest, rain in a flow rate of more than 1 liter per square meter per minute (l / (m2.min) is applied during 7 hours and 50 minutes. Another 10 minutes break finalizes the cycle. Two series of 7 cycles are applied, with between the two series heat of 60°C is applied during 3 days. The tape test has a score from 0 to 10, wherein 10 indicates undamaged, 8 indicates a damage of less than 5%, 6 means a damage of 5-15%, 4 indicates a damage of 15-35%, 2 a damage of 35-65% and 0 more than 65% damage. Data in the table are based on an arithmetic average of at least 3 samples.

[0053]

[0054] Table 2 - results of table test after freeze-thawing and heat-rain test

[0055] It is apparent from these data that products in accordance with the invention have better adhesion of the coating on the side edges than the reference products. Furthermore, the results in the freeze-thaw tests and the heat test show that the durability of the produces in accordance with the invention has been improved significantly.

[0056] In order to corroborate quality of the resulting products, coating thicknesses were measured. Thickness of the coating refers to total coating thickness. On the main surface, this includes the primer and the coating of the coating system and the first UV-cured transparent layer. On the side edge, this includes the primer and the coating of the coating system. The thickness of the transparent UV-cured coatings is an average coating thickness for each transparent UV-cured coatings applied on top of the print.

[0057]

[0058] Table 3 - layer thicknesses of coatings. All values in micrometers (pm)

[0059] It is apparent from Table 3 that the products made according to Process 2 have lower coating thickness on the first main surface. Nevertheless, the adhesion as defined in the tape test before and after freeze-thawing cycles and heat-rain cycles is good. The thickness of the coating made in accordance with Process 2 on the side edge is higher, which may have contributed to the positive results achieved thereon.

Claims

Claims1. A coated fiber cement product provided with a print, comprising:A substrate of autoclave-cured fiber cement material, which substrate is provided with a first and second opposed main surfaces and side edges extending between said main surfaces;A coating system applied on at least said first main surface and said side edges, wherein the coating system comprises a primer and a colored coating;A first UV-cured transparent coating on said coating system, which first UV-cured transparent coating is present on the first main surface;A print on top of the first UV-cured transparent coating, said print comprising a printed pattern of ink, andA second UV-cured transparent coating on top of said print.

2. The coated fiber cement product as claimed in claim 1, wherein the substrate of fiber cement material has a density of at least 1.2 kg / dm3 and less than 1.5 kg / dm3 and wherein said first main surface is a textured surface.

3. The coated fiber cement product as claimed in claim 1 or 2, wherein the substrate of fiber cement material has a porosity in the range of 30% to 45%, and / or wherein the fiber cement substrate is autoclave-cured without preceding compression step.

4. The coated fiber cement product as claimed in any of the preceding claims, wherein at least the primer of said coating system further extends on the second main surface of the fiber cement substrate.

5. The coated fiber cement product as claimed in any of the preceding claims, wherein at least one of said first and second transparent coatings comprise a pigment or a filler.

6. The coated fiber cement product as claimed in claim 5, wherein the said at least one transparent coating has a pigment volume concentration in the range of 0.01 to 3%, wherein the pigment volume concentration can be calculated via the following mathematical formula: " pigment volume concentration " expressed in % = " PVC " expressed in % = volume of pigments + volume of fillers / (volume of pigments + volume of fillers + volume of solid binder(s)) * 100 expressed in %.

7. The coated fiber cement product as claimed in any of the preceding claims, wherein said textured surface comprises a series of ridges and grooves, especially in the form of a wood structure.

8. The coated fiber cement product as claimed in any of the preceding claims, wherein a total dry thickness of the coating system, the first and second transparent coatings and the print is less than a maximum height of texture of the textured surface.

9. The coated fiber cement product as claimed in any of the preceding claims, wherein the first and second transparent UV cured coating layers are provided in a layer thickness of in the range of 6 to 9 g / m2.

10. The coated fiber cement product as claimed in any of the preceding claims, wherein the colored coating of the coating system has a pigment volume concentration (PVC) in the range of 15 to 30%.

11. The coated fiber cement product as claimed in any of the preceding claims, further comprising an intermediate transparent coating covering the print and a second print comprising a printed pattern of ink on top of said intermediate transparent coating, wherein said second UV-cured transparent coating covers said second print.

12. Method of manufacturing a coated fiber cement product comprising the steps of:Providing a substrate of autoclave-cured fiber cement material, which substrate is provided with a first and second opposed main surfaces and side edges extending between said main surfaces;Applying a coating system on at least said first main surface and said side edges of said substrate, wherein applying the coating system comprises applying a primer onto said surfaces of the substrate and applying a colored coating onto the primer;Applying a first UV-curable transparent coating on said coating system, which first transparent UV-curable coating is present on the first main surface, and curing said UV-curable transparent coating by UV-radiation;Providing a printed pattern of ink on top of the first UV-cured transparent coating, Applying a second UV-curable transparent coating covering said print and said first UV-cured transparent coating, and curing said second UV-curable transparent coating.

13. Method as claimed in claim 12, wherein said first main surface of the fiber cement substrate is a textured surface, and wherein the substrate has a density of at least 1.2 kg / dm3and less than 1.5 kg / dm3.

14. Method as claimed in claim 13, wherein the ink is a solvent-based ink, and wherein said solvent-based ink is dried after its application on the first UV-cured transparent coating.

15. Method as claimed in claim 13 or 14, wherein the provision of the fiber cement substrate comprises the steps ofmanufacturing a green substrate of fiber cement material using a fiber cement; manufacturing process startingfrom an aqueous slurry comprising fibers and cement, preferably using the Hatschek process, andcuring the green substrate by means of an autoclave-curing treatment.

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