PLASTIC-BOARDED WORKTOP

Description

Technical field

[0001] The invention relates to a worktop made of rock granules bound by a curable polymer and optionally additives influencing the external appearance. State of the art

[0002] To utilize the exceptional hardness of quartz for worktops, it is known to mix quartz-based minerals, typically comprising more than 80% by weight, with a polymer binder and compact the mixture in a mold using mechanical pressure until it is pore-free. The polymer hardens in the mold, allowing the composite material, formed into a worktop, to be removed. Depending on the desired appearance, sand, color pigments, and even small pieces of glass can be added to the fine-grained quartz to achieve special effects. A disadvantage, however, is that such worktops have limited heat resistance, which restricts their use, particularly in kitchens.

[0003] US 2022 / 089485 A1 discloses an artificial agglomerate stone material suitable for the production of a block, slab, board or plate by vibration compaction, consisting of 85-95 wt.% inorganic fillers, including -- a total of 50-70 wt.% based on the stone material: --- 2-50 wt.%, based on the stone material, feldspar granules (particle size D90 10-40 µm) of a specific oxide combination of formula A and a specific oxide combination of formula B, --- 20-48 wt.% preferably recycled silicate glass granules (particle size 63-300 µm), 5-15 wt.% cured organic resin (listed includes polyester resin).

[0004] Emphasis is placed on limiting the content of crystalline silica (as an impurity in feldspar) in the filler to preferably 0-7 wt%. Description of the invention

[0005] The invention is therefore based on the objective of creating a worktop which, in terms of hardness and abrasion resistance, is quite comparable to a worktop made of a quartz-based, resin-bonded composite material, but which, in contrast to such a quartz composite, has a significantly higher heat resistance.

[0006] Starting from a worktop of the type described above, the invention solves the problem by comprising a mixture of 25 to 50 wt.% of a rock from a group of rocks including metamorphic hard rocks, granite, gabbro and volcanic rock with a grain size between 0.2 and 0.8 mm, 0 to 20 wt.% glass granules and 37 to 75 wt.% feldspar with a grain size up to 0.8 mm.

[0007] Metamorphic hard rocks, but also granite, gabbro, and volcanic rocks, which should have a Mohs hardness of at least 5, preferably at least 6, with regard to the required hardness and abrasion resistance, increase the heat resistance of the worktops manufactured from them surprisingly significantly compared to quartz composites, namely by an average of 40 to 50 °C and more, so that worktops according to the invention can also be advantageously used in kitchen areas. In addition to SiO₂ and Na₂O, the feldspar (NaAlSi₃O₈) also contributes alumina (Al₂O₃) to the mixture, which leads to an increase in chemical resistance to water, food, and environmental influences. The water absorption of worktops according to the invention is approximately 0.02%.

[0008] The feldspar can advantageously originate from a pre-production stage of the ceramics industry. The portion of feldspar that is unsuitable for ceramic production due to quality reasons, sorted out, or otherwise discarded, is well suited for the application according to the invention.

[0009] The appearance of the worktop can be influenced by appropriate additives, such as pigments. Glass is particularly suitable as an additive and can constitute up to 20% by weight of the mixture. A glass granulate content of 13 to 19% by weight is preferred. For the specified proportion of metamorphic hard rock, granite, gabbro, or volcanic rock, this translates to a feldspar content of 37 to 56% by weight in the mixture.

[0010] Suitable rocks include granite, gabbro, gneiss and volcanic rock, and it is quite possible to use several types of hard rock together in a mixture to achieve special effects.

[0011] The mixture is bound in a manner known per se using a suitable heat-curing polymer, which is preferably added to the mixture in an amount of 9 to 12 wt.% before the mixture containing the binder is cured in a mold under heat and pressure in the usual way. Ways to implement the invention Example implementation:

[0012] Thirty-seven parts by weight of Brazilian granite with an average grain size of 0.5 mm are mixed with nine parts by weight of glass granules and 44 parts by weight of feldspar with a grain size up to 0.8 mm, with the addition of ten parts by weight of a polymeric ester resin-based binder. The mixture is then cured in a mold under heat and pressure. Compaction is achieved through a combination of vacuum and vibration treatment followed by pressure treatment at < 40 kg / cm². The curing temperature is 85–90 °C.

Claims

1. Worktop made from a mixture of fine-grained rock granulate bound by a curable polymer and, if desired, at least one additive that influences the external appearance, characterised in that the mixture comprises 25 to 50% by weight of a rock selected from a group of rocks comprising metamorphic hard rock, granite, gabbro and volcanic rock, with a grain size between 0.2 and 0.8 mm, 0 to 20% by weight of glass granulate and 37 to 75% by weight of feldspar with a grain size of up to 0.8 mm.

2. Worktop according to claim 1, characterised in that the glass granulate accounts for 13 to 19% by weight and the feldspar accounts for 37 to 56% by weight of the mixture.

3. Worktop according to claim 1 or 2, characterised in that the mixture comprises at least one rock selected from a group of rocks comprising granite, gabbro, gneiss and volcanic rock.