METHOD FOR MANUFACTURING AN ENGINEERED STONE AND AN ENGINEERED STONE

Abstract

A method for manufacturing an engineered stone comprising the steps of: providing a mixture comprising at least a stone or stone like material and a binder; compacting the mixture; curing the binder; and printing a printed pattern on at least a top surface of the engineered stone.

Claims

1. A method for manufacturing an engineered stone comprising the steps of: providing a mixture comprising at least a stone or stone like material and a binder; adding a coloring agent to the mixture in such a manner to provide a basic dcor; compacting the mixture; curing the binder to form an engineered stone; polishing the top surface of the cured engineered stone; printing a pattern with at least one sublimation ink on a first surface of the engineered stone, the first surface being a top surface of the engineered stone; fixing the sublimation ink via application of heat and/or pressure; wherein the printing step comprises inkjet digital printing, wherein the printing step is performed after the curing step, and wherein the basic dcor and the printed pattern are both visible on at least the top surface of the engineered stone.

2. The method according to claim 1, wherein the basic dcor is a veined effect imitating a natural stone.

3. The method according to claim 1, wherein said basic dcor is formed by random color shades in the engineered stone.

4. The method according to claim 1, further comprising the step of providing a protective layer to at least partially coat at least the top surface of the engineered stone.

5. The method according to claim 4, wherein the protective layer is transparent or translucent and is provided above the printed pattern.

6. The method according to claim 4, wherein the protective layer comprises a hardenable resin.

7. The method according to claim 6, wherein the protective layer comprises an acrylic or epoxy resin.

8. The method according to claim 6, further comprising the step of hardening the protective layer comprises curing and/or drying the protective layer.

9. The method according to claim 1, further comprising the step of providing a primer to the surface of the engineered stone before the step of printing.

10. The method according to claim 9, wherein the primer is acrylic, methacrylic, polyurethane, water based, solvent based or styrene.

11. The method in accordance to claim 9, wherein the primer is provided by means of a spray or rollers.

12. The method according to claim 4, further comprising a finishing step comprising polishing the surface of the engineered stone after the protective layer has been provided.

13. The method according to claim 1, wherein the printed pattern is applied in a fixed relationship to a predetermined point.

14. The method according to claim 1, wherein the printing step comprises detection of the upcoming engineered stone, and using this detection to control a printer.

15. The method according to claim 1, further comprising matching the printed pattern and the basis dcor together to form a single image or decoration that continues from one surface to the other.

16. The method according to claim 1, wherein the printed pattern is a veined effect imitating a natural stone.

17. The method according to claim 1, wherein during curing of the engineered stone, a heating step is conducted at a temperature below 500 C.

18. The method according to claim 1, wherein during curing of the engineered stone, a heating step is conducted at a temperature below 200 C.

19. The method according to claim 1, wherein the binder comprises a polyester resin preferably an unsaturated polyester resin.

20. The method according to claim 1, wherein the stone or stone like material comprises a siliceous mineral material, for example quartz, silica sand, clay, feldspar cristobalite granite, or talc.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0056] With the intention of better showing the characteristics of the invention, in the following, as an example without any limitative character, several preferred embodiments are described with reference to the accompanying drawings, wherein:

[0057] FIG. 1 is a perspective view of an engineered stone in accordance with the invention;

[0058] FIG. 2 on a larger scale shows the cross section along the line II-II indicated in FIG. 1;

[0059] FIG. 3 on a larger scale shows a view on the area F3 indicated on FIG. 2;

[0060] FIG. 4 on a larger scale shows a view on the area F3 indicated on FIG. 2 according to a different embodiment;

[0061] FIG. 5 shows some steps of a method in accordance with the invention;

[0062] FIG. 6 shows some steps of a method in accordance with a variant of the invention;

[0063] FIG. 7 shows some steps of a method in accordance with a further variant of the invention;

[0064] FIG. 8 shows some steps of a method in accordance with still another variant of the invention;

[0065] FIG. 9 on a larger scale shows a view on the area F3 indicated on FIG. 2 before the engineered stone is polished;

[0066] FIG. 10 is a perspective view of a countertop comprising an engineered stone in accordance with the invention;

[0067] FIG. 11 is a view along direction F11 of FIG. 1 of the engineered stone according to a still alternative embodiment;

[0068] FIG. 12 shows some steps of a method in accordance with a further variant of the invention for the manufacturing of the engineered stone of FIG. 11;

[0069] FIG. 13 on a larger scale shows a view on the area F3 indicated on FIG. 2 according to another different embodiment;

[0070] FIG. 14 on a larger scale shows a view on the area F14 indicated on FIG. 13;

[0071] FIG. 15 shows some steps of a method in accordance with a further variant of the invention for the manufacturing of the engineered stone of FIGS. 13 and 14;

DETAILED DESCRIPTION

[0072] Referring to FIG. 1 there is shown an engineered stone 1 comprising a stone or stone like material and a cured binder that bonds together the particles of stone or stone like material. The engineered stone 1 is preferably made in form of a slab 2 having a length X of at least 2 m, preferably at least 2.5 m, for example 3 m or more, and a width Y of at least 1 m preferably 1.5 m or more. Moreover, the engineered stone shows a thickness Z of at least 10 mm, preferably at least mm for example 30 mm.

[0073] The engineered stone 1 comprises at least a top surface 3 provided with a printed pattern 4. The printed pattern 4 can represent any dcor, design or inscription, although it is preferred that the printed pattern 4 represents an imitation of a natural stone, i.e., represents the veins and/or flakes of a natural stone like a marble or a granite.

[0074] According to a variant of the invention, the engineered stone 1 can comprise a basic dcor 5 defining a background for the printed pattern 4. For example, the basic dcor 5 represents an imitation of a natural stone, i.e., represents the veins and/or flakes of a natural stone like a marble or a granite. In this case the printed pattern 4 above the basic dcor 5 can represent special features or special effects of the imitated natural stone. As shown from FIGS. 2 and 3, the basic dcor 5 is preferably created on the entire thickness of the engineered stone 1 so that it is visible also from the lateral side of the engineered stone 1 and preferably from any section of the engineered stone 1 itself.

[0075] According to a preferred embodiment, the top surface 3 of the engineered stone 1 is smooth, for example polished. FIG. 4 shows an alternative embodiment wherein the top surface 3 comprise a relief structure 6, for example comprising protrusions and/or excavations. Preferably the relief structure 6 comprises features related to the basic dcor 5 and/or the printed pattern 4, for example the relief structure 6 comprises protrusions and/or excavations that runs substantially parallel with respect to the veins of the imitated natural stone represented by the basic dcor 5 and/or the printed pattern 4.

[0076] FIG. 5 shows a method for manufacturing the engineered stone 1 illustrated in figures from 1 to 4. The method comprises the step S1 of providing a mixture M comprising at least a stone or stone like material and a binder.

[0077] The stone or stone like material can comprise any kind of stone, sands, siliceous mineral material, for example quartz, silica sand, clay, feldspar cristobalite granite, talc, or calcareous mineral material, for example, calcium carbonate, marble, gypsum. The stone or stone like material can also comprise ceramic, glass, metals, and other inorganic material, for example recycled materials. The stone or stone like material can be in form of powder, granules, shards, or any other particulate form although powder form is preferred. Preferably the stone or stone like material is in powder form having an average particle dimension less than 45 m, preferably less than 20 m. The stone or stone like material is preferably at least 80% by weight of the mixture, preferably more than 85% and more preferably more than 90%. According to another embodiment of the invention the stone or stone like material can be in form of aggregates, grains and/or granules having a particles size distribution between 0.1 and 0.7 mm. According to still another embodiment of the invention the stone or stone like material comprises at least 60 wt % of grains and/or granules having a particles size distribution between 0.1 and 0.7 mm and between 20 to 35 wt % of powder form having an average particle dimension less than 45 m, preferably less than 20 m.

[0078] The binder is a curable substance that is configured to be cured thereby bonding together the particles of the stone or stone like material. The binder can be in any form, i.e., liquid, solid, gel or any form that is suitable to be mixed with the stone or stone like material and to be homogeneously dispersed within. Preferably, the binder is in powder or pellet form. Although any kind of curable substance can be used, heat curable substances are preferred. The binder can be an organic substance, for example a resin, or an inorganic substance, for example a concrete or silica.

[0079] According to the preferred embodiments shown in FIGS. 5 to 8, the binder is a thermosetting resin like embodiment, for example, the binder is polyester, polystyrene, acrylic, or epoxy resin. The binder is preferably less than 20% by weight of the mixture, preferably less than 15% and more preferably less than 10%.

[0080] The mixture M can also comprise additives, like for example catalysts or reagents to activate or speed up hardening of the binder, and/or temporary bonding agent like glues or thermoplastic resins that temporarily bonds the stone or stone like material.

[0081] Moreover, the mixture M can comprise fillers, for example inorganic fillers like sand, quarts, feldspar, silica, calcium carbonate in fine powder form to reinforce the binder that fills the interstices between the stone or stone like material particles. The fillers are preferably mixed to the binder, for example they are dispersed into the resin or the cement to form a binding past or are binder pellets destined to be mixed with the stone or stone like material for forming the mixture.

[0082] The components of the mixture M are mixed together and are provided on a temporary support 10 by means of a feeding device 11, for example a hopper. The temporary support 10 can be a mold, a frame, a tray, or a conveyor, for example a conveyor having lateral containment means for providing the mixture of a shape similar to that of the final slab. In the embodiment shown in FIG. 5 the temporary support 10 is in the form of a mold 12 carried by a first conveyor 13, for example a conveyor belt, through the direction A.

[0083] According to a preferred embodiment shown in the figures, the mixture M is provided in form of an incoherent particulate, and comprises a first particulate of stone or stone like material and a second particulate of binder mixed together, preferably in powder form for example into the feeding device 11.

[0084] The method can further comprise the step of forming the basic dcor 5 on the engineered stone 1. In the embodiment shown FIG. 5 a computer controlled machine 14, for example an anthropomorphous robot can distribute a coloring agent on the engineered stone. According to a preferred embodiment the computer controlled machine is provided with a nozzle for delivering the coloring agent that is connected to a tool, like a knife or a mill, that is configured for forming grooves or recesses, into the mixture M inside the temporary support 10, adapted to receive the coloring agent. Thus, the computer controlled machine 14 can create colored lines or spots for example defining the veins of a natural stone following a predetermined input received from a computer.

[0085] FIG. 6 shows an alternative embodiment of adding the coloring agent, wherein the coloring agent is provided by free falling from a coloring agent feeder 15 feeder onto the mixture M. More in detail, the mixture M is firstly fed on a temporary conveyor 16 placed substantially above the temporary support 10 so that it can free fall on the temporary support from an end of the temporary conveyor 16. The coloring agent is fed from the coloring agent feeder 15 onto the top surface of the mixture M substantially in correspondence of the end of the temporary conveyor 16 so that the mixture and the coloring agent contemporary free fall on the temporary support 10 and the coloring agent is randomly dispersed into the mixture M.

[0086] Referring back to FIG. 5, the method comprises the step S2 of printing the printed pattern 4 onto the top surface of the engineered stone 1, preferably by printing an ink. In the example, the temporary support 10 conveyed by the first conveyor 13 is conveyed to a printing station 20 provided with a printing device 21. According to a preferred embodiment shown in FIG. 5 the printing device 21 is a digital printer, preferably an inkjet digital printer.

[0087] For example, the printing device 21 is an inkjet digital printer comprising a printing head adapted to print with four or more colors. More in detail, the printed pattern 4 can be obtained by means of multiple color inks, for example with four colors, preferably cyan, magenta, yellow and black, or more colors, for example seven or eight colors.

[0088] According to a preferred embodiment organic inks are used for providing the printed pattern 4 on the engineered stone 1. Preferably the inks are curable inks, for example UV, IR or heat curable inks.

[0089] The method further comprises the step S3 of compacting the mixture M. according to the embodiment shown in FIG. 5, the mold 12 conveyed to the first conveyor 13 is moved to a compacting station 30 comprising a press 31 configured to apply a pressure to the Mixture M into the mold 12. In the present embodiment, the mold 12 is the same used as temporary support 10 but it is clear that according to a different embodiment the mold 12 used in the press 31 can be different from the temporary support 10.

[0090] Preferably the compacting station 30 comprises also a vibrating unit 32 configured to apply a vibration to the mixture during the compacting step S3. Moreover, according to the preferred embodiment, the compacting station 30 comprises also a vacuum unit 33 configured to create vacuum into the mold 12 during the compacting step S3.

[0091] In the embodiment shown in FIG. 5, with reference to FIG. 9 also, the vibration applied to the mixture M during the compacting step S3 helps the ink of the printed pattern 4 to permeate the mixture M so to penetrate through the top surface 3 of the slab for a penetration depth P of at least 0.5 mm starting from the top surface, more preferably of 1 mm, for example of 2 mm.

[0092] The method further comprises a curing step S4 for curing the binder of the mixture M thereby bonding together the stone or stone like materials and, thus, obtaining the slab 2 of engineered stone 1. According to the embodiment shown in FIG. 5 the compacted mixture is moved from the compacting station 30 to a second conveyor 34 that conveys the compacted mixture M to a curing station 40.

[0093] According to a preferred embodiment, the curing station 40 comprises a heating device 41 configured to heat curing the mixture M, i.e., it is configured to heat the mixture M up to the curing temperature of the binder. Preferably the heating temperature is below 200 C., more preferably below 100, for example 90 C.

[0094] The method, according to the invention, can further comprise one or more machining steps S5, for example a polishing step. According to a preferred embodiment shown in the figures the engineered stone is moved by the second conveyor 34 to a machining station 50 comprising a polishing device 51. The polishing device 51 is configured to polish the top surface 3 of the slab 2. Preferably the polishing step S5 is conducted in such a way to remove a very limited amount of material from the top surface 3 of the slab, and in particular it is conducted in such a way that after the polishing step the printed pattern 4 is visible from the top surface 3 of the slab 2. For example, the polishing step S5 is conducted in such a way to remove less than less than 2 mm of the thickness of the slab, preferably less than 1 mm, for example 0.5 mm, i.e., less than the penetration depth P from the top surface 3.

[0095] The method can comprise further machining steps S5, like for example cutting, drilling, or milling step. For example, the machining station 50 can comprise a cutting device for cutting the slab 2 according to the shape and dimension of the design of the desired final use of the engineered stone 1.

[0096] For example, FIG. 10 shows a countertop 80 comprising the engineered stone 1, for example made starting from the slab 2, that comprises through holes 81 for accommodating a hob, a washtub, a socket, or any other item.

[0097] FIG. 7 shows a different embodiment of the method wherein the printing step S2 is conducted after the compacting step S3 and before the curing step S4. In this case the ink printed pattern 4 can still permeate the mixture through the interstices between the particles of stone or stone like material since the binder is not yet cured.

[0098] FIG. 8 shows a further embodiment, wherein the printing step S2 is conducted after the heating step S4. In this case, the method can comprise a print curing step S6 for curing the printed pattern on the already cured engineered stone 1. For example, the engineered stone 1 is conveyed by the second conveyor 33 from the curing station 40 to the printing station 20 and from the printing station 20 that comprises a print curing device 22.

[0099] FIG. 11 shows a further embodiment of the invention wherein the slab 2 comprises edges 7 provided with the printed pattern 4. FIG. 12 shows a method for forming the slab 2 of FIG. 9 wherein subsequent printing steps S2, S2, S are conducted in a sequential order and wherein each printing step S2, S2, S2 for printing on a different surface with respect to the others printing steps. According to this embodiment the printing station 20 can comprise a plurality of printing devices 21 wherein each printing device 21 is configured to print on a different surface.

[0100] FIG. 13 shows an embodiment of the invention wherein the engineered stone 1 comprises a protective layer 8 coating partially or entirely at least the top surface 3 of the engineered stone 1. In the embodiment shown the protective layer 8 is provided above the printed pattern 4 and it is preferable a transparent or translucent layer. For example, the protective layer 8 is a curable resin like an acrylic or epoxy resin.

[0101] As shown in FIG. 14, the protective layer 8 advantageously comprises fillers 9, like corundum, silver, titanium dioxide, or others, dispersed therein to improve the superficial properties of the engineered stone 1 like for example wear and scratch resistance and antimicrobial behavior.

[0102] FIG. 14 shows a method for forming the engineered stone 1 of FIG. 13 that, subsequent printing steps S2, comprises the step S7 of providing the protective layer 8 above the printed pattern 4. In the example shown in FIG. 12 the coating step S7 is conducted before the curing step S4 so that the protective layer 8 is cured together with the ink and the engineered stone 1. According to said embodiment the engineered stone 1 is conducted from the printing station 20 to a coating station 70 provided with at least a coating device 71, for example a roller or a sprayer, configured to provide the protective layer 8 above the printed pattern 4, subsequently the compacted mixture is carried to the curing station S4 to be cured.

[0103] The present invention is in no way limited to the hereinabove described embodiments, but such floor, floor covering, and floor elements may be realized according to different variants without leaving the scope of the present invention.

[0104] Further, as is clear from the content of the description, the present invention relates to one or more of the items as listed below, numbered from 1 to 21: [0105] 1.A method for manufacturing an engineered stone (1) comprising the step of: [0106] providing (S1) a mixture (M) comprising at least a stone or stone like material and a binder; [0107] compacting (S3) the mixture (M); [0108] curing (S4) the binder; [0109] and wherein the method comprises the step of printing (S2) on at least a top surface (3) of the engineered stone (1). [0110] 2.The method according to item 1, wherein the printing step (S2) is a digital printing step. [0111] 3.The method according to item 2, wherein the printing step (S2) is an inkjet digital printing step. [0112] 4.The method according to any of the previous items, wherein the printing step (S2) is conducted before the curing step (S4). [0113] 5.The method according to any of the previous items, wherein the printing step (S2) is conducted before the compacting step (S3). [0114] 6.The method according to any of the previous items, wherein the mixture (M) is provided on a temporary support (10) and the printed pattern (4) is provided on a top surface (3) of the mixture (M) on the temporary support (10). [0115] 7.The method according to any of the previous items, wherein the printed pattern (4) is formed with at least an organic ink. [0116] 8.The method according to any of the previous items, wherein the printed pattern (4) is formed with at least an inorganic ink. [0117] 9.The method according to any of the previous items, wherein it comprises the step of adding a coloring agent to the mixture (M) to provide a basic color. [0118] 10.The method according to any of the previous items, wherein it comprises the step of adding a coloring agent to the mixture (M) in such a manner to provide a basic dcor (5). [0119] 11.The method according to item 10, wherein the basic dcor (5) is a veined effect imitating a natural stone. [0120] 12.The method according to any of the previous items, wherein it comprises a further step of printing a printed pattern (4) on a surface (8) that is different with respect to the top surface (3) of the engineered stone (1). [0121] 13.An engineered stone (1) comprising a stone or stone like material and a binder bonding together the stone or stone like material wherein it comprises at least a top surface (3) having a printed pattern (4). [0122] 14.The engineered stone (1) according to item 13, wherein the printed pattern (4) is a digital printed pattern. [0123] 15.The engineered stone (1) according to any of items 13 or 14, wherein it further comprises a basic dcor (5). [0124] 16.The engineered stone (1) according to item 15, wherein the basic dcor (5) is present in to the entire thickness of the engineered stone. [0125] 17.The engineered stone (1) according to any of items from 13 to 15, wherein it comprises a further surface (8) different with respect to the top surface (3) and wherein the further surface (8) is provided with the printed pattern (4). [0126] 18.The engineered stone (1) according to any of items from 13 to 16, wherein the engineered stone (1) is in form of a slab (2). [0127] 19.The engineered stone (1) according to item 18, wherein the slab (2) has a width (Y) of at least 1 mm and a length (X) of at least 2 m. [0128] 20.The engineered stone (1) according to item 18 or 17, wherein the slab (2) has a thickness (Z) 25 of at least 10 mm. [0129] 21.A countertop (80) comprising an engineered stone (1) and comprising at least a top surface (3) having a printed pattern (4).