Agglomerated Stone Countertop and Process of Manufacture

Abstract

The present invention provides a countertop (10) comprising a backer sheet (16) of a relatively lightweight, rigid material; an outer layer (14) of agglomerated stone disposed on a top surface (16a) of the backer sheet (16) to create a central portion (14a) of the countertop; and an outer layer (14) of agglomerated stone disposed on a side surface (16c, 16d) of the backer sheet (16) to create an edge portion (14b, 14c) of the countertop (10); wherein the central portion (14a) and edge portion(s)(14b, 14c) form a one piece agglomerated stone layer (14). The present invention also provides a moulding process to manufacture the agglomerated stone countertop (10).

Claims

1. A countertop (10) comprising: a backer sheet (16) of a relatively lightweight, rigid material; an outer layer of agglomerated stone (14) disposed on a top surface (16a) of the backer sheet (16) to create a central portion (14a) of the countertop; and an outer layer of agglomerated stone (14) disposed on a side surface (16c, 16d) of the backer sheet (16) to create an edge portion (14b, 14c) of the countertop (10); wherein the central portion (14a) and edge portion(s) (14b, 14c) form a one piece agglomerated stone layer (14).

2. A countertop (10) comprising: a honeycomb backer sheet (16) having a top surface (16a), a bottom surface (16b) and one or more side surfaces (16c, 16d) extending between the top and bottom surfaces; a layer of agglomerated stone bonded (14) to the top surface (16a) of the backer sheet (16) defining a top portion (14a) of the countertop (10); a layer of agglomerated stone (14) bonded to at least one side surface (16c, 16d) of the backer sheet (16) defining an edge portion (14b, 14c) of the countertop (10); wherein the agglomerated stone covering the top surface (14a) and the at least one side surface (14b, 14c) of the backer sheet (16) is a one-piece layer (14) of agglomerated stone.

3. A countertop according to claim 1, wherein the agglomerated stone comprises about 85 to about 98% by weight of stone aggregates.

4. A countertop according to claim 1 wherein the agglomerated stone comprises a resin as a binder.

5. A process for the manufacture of an agglomerated stone countertop (10), comprising the steps of: providing a mould (24) having a mould cavity defined therein, the mould cavity corresponding to a countertop (10), and including a bottom surface (24a) which corresponds to a top (12a) or a bottom surface of the countertop (10), and a side wall (24b, 24c) which corresponds to an edge surface (12b) of the countertop; providing a backer sheet (16) having a top surface (16a), a bottom surface (16b) and side surfaces (16c) extending between the top and bottom surfaces; providing an agglomerated stone composition (26); disposing the backer sheet (16) and the agglomerated stone composition (26) in the mould cavity such that the backer sheet (16) partially fills the mould cavity in a spaced apart relationship with at least one side wall (24b, 24c) of the mould cavity; and the agglomerated stone composition (26) fills the space between the side surfaces (16c, 16d) of the backer sheet (16) and the side wall (24b, 24c) of the mould cavity and covers the bottom or top surface (16a) of the backer sheet (16); and curing the stone composition.

6. A process according to claim 5, wherein the backer sheet (16) is first disposed on the bottom surface (24a) of the mould cavity and the agglomerated stone composition (26) is subsequently disposed over the top surface (16a) of the backer sheet (16) and in the space defined between the side surfaces (16c, 16d) of the backer sheet (16) and the side walls (24b, 24c) of the mould cavity.

7. A process according to claim 6, further comprising applying pressure and/or vibration to the contents (16, 26) of the mould (24).

8. A process according to claim 7 further comprising trimming at least one edge (14b, 14c) of the layer (14) of cured stone composition (24).

9. A process according to claim 8 wherein the backer sheet (16) comprises a material of honeycomb structure.

10. A process according to claim 9, wherein the honeycomb structure comprises a plastics material.

11. A countertop according to claim 2, wherein the agglomerated stone comprises about 85 to about 98% by weight of stone aggregates.

12. A countertop according to claim 11 wherein the agglomerated stone comprises a resin as a binder.

13. A process according to claim 6 further comprising applying pressure and/or vibration to the contents (16, 26) of the mould (24).

14. A process according to claim 5, wherein the backer sheet (16) comprises a material of honeycomb structure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG. 1 shows a perspective view of an embodiment of a countertop according to the invention, with a section of the honeycomb backer sheet material removed;

[0040] FIG. 2 shows a perspective view of the honeycomb backer sheet material used in the countertop of FIG. 1;

[0041] FIG. 3 shows a side sectional view of an agglomerated stone composition in a mould according to a conventional process; and

[0042] FIG. 4 shows a side sectional view of an agglomerated stone composition in a mould according to the process of the invention.

DETAILED DESCRIPTION

[0043] The process for manufacturing agglomerated stone countertops or slabs according to the present invention produces slabs having the appearance and performance characteristics that are equal or superior to solid slabs produced according to known methods. The slabs produced also weigh significantly less that the slabs manufactured according to the known method, thereby making them easier to transport and install, and cost less to manufacture.

[0044] Referring to the Figures, in FIG. 1 a countertop (10) according to the invention has an outer surface (12) formed of a continuous layer (14) of agglomerated quartz made up of a central portion (14a) and edge portions (14b, 14c). The central portion has a thickness of 8-10 mm and the edge portions (14b, 14c) each have a thickness of 40 mm.

[0045] The quartz layer (14) of the countertop (10) is supported by a backer sheet material (16), which has a top surface (16a), a bottom surface (16b) and side surfaces (16c, 16d) extending between the top and bottom surfaces. The backer sheet (16) is fused at its top surface (16a) and side surfaces (16c) to the quartz layer (14). A protection layer (18) of 1 mm thickness is provided on the bottom surface (16b) of the backer sheet (16).

[0046] As illustrated in FIG. 2, the backer sheet material (16) consists of a honeycomb structure (22) sandwiched between continuous top (22a) and bottom (22b) layers. The sheet material (16) is of the sort which is readily available and comprises a plurality of cells, generally hexagonal or octagonal in cross-section. Such material is capable of withstanding high compression forces, especially when such forces are distributed over the face of the honeycomb structure. The honeycomb structure, including its top and bottom layers, is made of polyvinylchloride (PVC).

[0047] FIG. 3 illustrates a step in a conventional moulding process for the manufacture of an agglomerated stone countertop.

[0048] After the raw materials are weighed and measured, they are transported to a mixer and mixed together. The mixture (26) comprises 93% by weight quartz particulates and 7% by weight of a polymer resin ((66% quartz and 34% resin by volume) in combination with a bonding agent to promote the adhesion of the resin to the stone particulates and additives that include pigments and UV stabilizer. The mixed materials are then poured into a metal mould (24) or other suitable carrier that which can be used to transport the formed slab into a vacuum vibration press (VVP).

[0049] The mould (24) includes a cavity defined therein which corresponds to the slab or countertop (10) to be manufactured. The mould (24) has a flat bottom surface (24a) which corresponds to the top surface (12a) of the countertop and side walls (24b, 24c) which correspond to edges (12b) of the countertop (10). One standard mould cavity has a width of 60 cm, a depth of 40 mm and a length of 3040 mm.

[0050] The slab is then pressed by means of a vacuum vibration process. This process is well known and involves a pressing mechanism and vibration device being configured to apply compressional and vibrational forces to the slab to force the stone granules into a close-packed configuration in which there is sufficient resin and stone powder to fill all remaining voids between the stone granules. A vacuum vibration press of Breton S.p.A may be used. Alternatively, a vibration device may be provided above and optionally also below the slab in a vacuum chamber so that the stone composition is simultaneously compressed and vibrated under vacuum.

[0051] Once the slab has been pressed, it is transported to an oven or to some other location for curing. Depending upon the adhesive (resin) used to bind the particles together into the slab, the curing and hardening process can take place at ambient temperature or at elevated temperature, such as at 70 or 80 C., and can require from a few minutes up to many hours. The heating can be done by any available means of providing a heat source, such as radiant heat, forced-air heated ovens, electric ovens and the like. After curing and hardening, the slab is returned to room temperature (if heat has been applied). Alternatively, the cured slab is cooled by passive cooling, such as free convection, or by active cooling, such as cooling the mould with some cooling agent, such as air, water or other fluid.

[0052] The cured slab is then calibrated and polished to a desired finish. The result is a finished stone slab that is non-porous and closely approximates the appearance and physical properties of natural stone slabs.

[0053] As illustrated in FIG. 4, according to the process of the present invention, a honeycomb backer sheet (16) is first disposed on the bottom surface (24a) of the empty mould (24) cavity. The backer sheet (16) is disposed in a spaced apart relationship with the side walls (24b, 24c) of the mould (24) cavity so as to define respective spaces therebetween. The agglomerated stone mixture (26) is then poured into the mould (24) cavity over the honeycomb sheet material (16) and in the spaces defined between the honeycomb sheet material (16) and the side walls (24b, 24c). In this manner, the stone composition (26) will form a thinner layer (14a) in the areas of the backer sheet but a full thickness layer (14b, 14c) proximate the edges.

[0054] Once the backer sheet (16) and stone mixture (26) are disposed in the mould (24), the next steps of the process are pressing and curing as described above. When the contents (16, 26) of the mould (24) are heated to cure the stone mixture (26), the stone mixture becomes bonded to the adjacent sheet material (16). After cooling, the resulting moulded stone countertop (10) is removed from the mould (24) and has a smooth outer stone surface (12), including an integral built up edge of stone material. The continuous hardened stone layer (14) is about 8 to about 10 mm thick at its thinnest and about 40 mm thick at its thickest.

[0055] It is noted that while the process is described with reference to the manufacture of a rectangular countertop, other shapes such as squares, circles, ovals and the like can be made by the present invention.

[0056] It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the scope of the present invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications are covered by the appended claims.