Composition for engineered stone and engineered stone manufactured therefrom

Abstract

The present invention relates to a composition for engineered stone and engineered stone manufactured therefrom, the composition comprising (A) 30 wt% to 60 wt% of glass sand, (B) 20 wt% to 40 wt% of glass powder, (C) 1 wt % to 40 wt% of silica powder, and (D) 9 wt% to 15 wt% of an unsaturated polyester resin.

Description

Composition for engineered stone and engineered stone produced therefrom

[0001] The present invention relates to a composition for engineered stone and engineered stone produced therefrom.

[0002] Natural stones such as granite and marble have long been used as architectural decorative materials due to their beautiful surface patterns. Recently, they have gained popularity as materials that exhibit high-quality textures, leading to a significant increase in demand in fields such as flooring, walls, and kitchen countertops. As a result, expensive natural stones alone can no longer meet this demand, leading to the development of various types of artificial stone.

[0003] Artificial stone is broadly classified into general artificial stone and resin-reinforced natural stone (also known as engineered stone). General artificial stone is manufactured by adding various additives, such as inorganic fillers, colorants, and curing agents, to acrylic or unsaturated polyester-based resins. Resin-reinforced natural stone replicates the texture of natural stone by compression molding a compound, which is a mixture of inorganic (silica-based) natural minerals and binder resin, using vibration or vacuum vibration.

[0004] Resin-reinforced natural stone is widely used for countertops and architectural finishing materials due to its high hardness and low water absorption, which prevents contamination. However, silica-based natural minerals used in resin-reinforced natural stone can be inhaled into the lungs, causing respiratory diseases; furthermore, the accumulation of silica dust in the lungs can induce inflammation, potentially leading to a decline in lung function. Recently, the Australian Health and Safety Authority issued a notice limiting the content of crystalline silica used in artificial stone due to concerns regarding silicosis; therefore, measures are needed to address the silicosis issue associated with resin-reinforced natural stone.

[0005] One embodiment provides a composition for engineered stone capable of exhibiting excellent physical properties and various colored appearances.

[0006] A composition for engineered stone according to one embodiment comprises (A) 30% to 60% by weight of glass sand, (B) 20% to 40% by weight of glass powder, (C) 1% to 40% by weight of silica powder, and (D) 9% to 15% by weight of unsaturated polyester resin.

[0007] The above (C) silica powder may be included in an amount of 1% to 25% by weight based on the total weight of the composition.

[0008] The particle size of the glass sand (A) above is 0.1 mm to 1.2 mm.

[0009] The particle size of the glass powder (B) above is 1 μm to 45 μm.

[0010] The particle size of the above (C) silica powder is 1 μm to 45 μm.

[0011] The weight-average molecular weight of the above (D) unsaturated polyester resin is 2,000 g / mol to 100,000 g / mol.

[0012] The above composition further includes (E) an organic pigment or an inorganic pigment.

[0013] The above (E) organic pigment or inorganic pigment is included in an amount of 0.5% to 5% by weight based on the total weight of the composition.

[0014] The above composition further comprises one or more additives selected from a curing agent, a curing accelerator, a crosslinking agent, a leveling agent, a UV absorber, a storage stabilizer, a polymerization inhibitor, a flame retardant, and an antistatic agent.

[0015] Another embodiment provides an engineered stone manufactured from the above-described composition for engineered stone.

[0016] The above engineered stone may have a flexural strength of 50 MPa to 95 MPa when measured at 3 mm / min according to ASTM D790 standards on a specimen with dimensions of 300 mm x 100 mm x 20 mm (width x height x thickness).

[0017] A composition for engineered stone according to one embodiment can be advantageously used to manufacture engineered stone used as a building material by reducing the silica content to reduce harmful elements to health and easily realizing excellent physical properties and various colors.

[0018] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and are not intended to limit the present invention, and the present invention is defined only by the appended claims.

[0019] Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning that is commonly understood by those skilled in the art to which the present invention pertains. Throughout the specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Furthermore, the singular form includes the plural form unless specifically stated otherwise in the text.

[0020] Unless specifically stated otherwise in this specification, particle size refers to the average particle size, which is the volume-average diameter, and means the Z-average particle size measured using a dynamic light scattering analyzer.

[0021] Unless otherwise specifically stated in this specification, the weight-average molecular weight is measured by dissolving the powder sample in a suitable solvent and then using Agilent Technologies’ 1200 series Gel Permeation Chromatography (GPC) (using Shodex’s polystyrene as the standard sample).

[0022] Conventional engineered stone uses compositions containing large amounts of silica, which has caused serious health problems for workers in industrial sites. In particular, inhaling crystalline silica dust can lead to silicosis or other respiratory diseases; consequently, Australia has recently recommended against the use of engineered stone containing large amounts of silica. Therefore, there was a demand for the development of engineered stone with reduced harmfulness to the human body. Accordingly, the inventors of the present invention have strived to develop a composition for engineered stone that is much safer to the human body while possessing physical properties equivalent to or superior to those of conventional engineered stone by using glass instead of silica. Accordingly, the engineered stone composition according to one completed embodiment achieves the aforementioned excellent physical properties and is much safer to the human body, while also enabling the realization of various colors that were difficult to achieve with existing engineered stone by using glass.

[0023] A composition for engineered stone according to one embodiment comprises (A) 30% to 60% by weight of glass sand, (B) 20% to 40% by weight of glass powder, (C) 10% to 40% by weight of silica powder, and (D) 9% to 15% by weight of unsaturated polyester resin.

[0024] The above (A) glass sand and (B) glass powder are main materials of a composition for engineered stone according to one embodiment, which can impart an appearance and texture similar to natural stone to the engineered stone and impart color to the engineered stone without using separate additives.

[0025] The above (A) glass sand and (B) glass powder can be obtained by recycling waste glass, for example, waste glass obtained by recycling construction materials, for example, waste glass obtained by recycling glass containers, glass ornaments, electronic devices, etc. By obtaining (A) glass sand and (B) glass powder by recycling waste glass, resources can be saved and it is environmentally friendly, and by using waste glass that retains its original color, various colors can be achieved without separate additives.

[0026] The above (A) glass sand is included in an amount of 30% to 60% by weight based on the total weight of the composition for engineered stone according to one embodiment, and may be included in an amount of, for example, 30% to 56% by weight or 30% to 50% by weight. Using (A) glass sand in the above content range can further improve processability while preventing a decrease in the mechanical properties of the composition for engineered stone containing it.

[0027] The particle size of the glass sand (A) above is 0.1 mm to 1.2 mm, and may be, for example, 0.2 mm to 1.2 mm, 0.3 mm to 1.2 mm, 0.4 mm to 1.2 mm, 0.5 mm to 1.2 mm, 0.6 mm to 1.2 mm, 0.7 mm to 1.2 mm, 0.1 mm to 1.0 mm, 0.1 mm to 0.7 mm, 0.1 mm to 0.5 mm, 0.1 mm to 0.4 mm, or 0.1 mm to 0.3 mm. If the particle size of the glass sand (A) is within the above range, a decrease in mechanical properties can be prevented.

[0028] A composition for engineered stone according to one embodiment can improve the mechanical properties of engineered stone by including (B) glass powder.

[0029] The above (B) glass powder is included in an amount of 20% to 40% by weight based on the total weight of the composition for engineered stone according to one embodiment, for example, 25% to 40% by weight. Using the (B) glass powder in the above content range can improve the mechanical properties of the composition for engineered stone containing it while minimizing the amount of unsaturated polyester resin used together with it.

[0030] The particle size of the (B) glass powder above is 1 μm to 45 μm, and may be, for example, 2 μm to 45 μm, 3 μm to 45 μm, 4 μm to 45 μm, 5 μm to 45 μm, 10 μm to 45 μm, 1 μm to 40 μm, 1 μm to 35 μm, 2 μm to 40 μm, 2 μm to 35 μm, 3 μm to 40 μm, 3 μm to 35 μm, 4 μm to 40 μm, 4 μm to 35 μm, 5 μm to 40 μm, 5 μm to 35 μm, 1 μm to 30 μm, 1 μm to 25 μm, or 1 μm to 20 μm. (B) If the particle size of the glass powder is within the above range, the processability of the composition for engineered stone containing it can be further increased, and the mechanical properties can be further improved.

[0031] A composition for engineered stone according to one embodiment includes (C) silica powder, which allows engineered stone manufactured therefrom to be formed densely, thereby improving mechanical properties.

[0032] The above (C) silica powder may be silica powder obtained by recycling silica used as molding sand, or silica powder obtained by recycling silica waste generated during silica mining and processing, but is not limited thereto and may be silica powder obtained by recycling from various industries. Using recycled silica powder saves resources and is environmentally friendly.

[0033] The above (C) silica powder is included in an amount of 1% to 40% by weight based on the total weight of the composition for engineered stone according to one embodiment, and may be included in an amount of, for example, 1% to 35% by weight, 1% to 30% by weight, or 1% to 25% by weight. By including the above (C) silica powder in the composition for engineered stone in the above content range, the content of crystalline silica included in the composition for engineered stone and the engineered stone produced therefrom is lowered, thereby making the composition for engineered stone containing the above or the engineered stone produced therefrom safer for the human body and solving the problem of engineered stone causing silicosis.

[0034] The particle size of the above (C) silica powder is 1 μm to 45 μm, and may be, for example, 2 μm to 45 μm, 3 μm to 45 μm, 4 μm to 45 μm, 5 μm to 45 μm, 10 μm to 45 μm, 1 μm to 40 μm, 1 μm to 35 μm, 2 μm to 40 μm, 2 μm to 35 μm, 3 μm to 40 μm, 3 μm to 35 μm, 1 μm to 30 μm, 1 μm to 25 μm, or 1 μm to 20 μm. If the particle size of the (C) silica powder is within the above range, it is similar in particle size to the (B) glass powder used together, which is advantageous for mixing, and the processability of the above engineered stone composition can be further improved.

[0035] A composition for engineered stone according to one embodiment includes (D) an unsaturated polyester resin to increase the bonding strength of the aforementioned (A) glass sand, (B) glass powder, and (C) silica powder, and can maintain excellent mechanical properties of the engineered stone produced from the composition for engineered stone.

[0036] The above (D) unsaturated polyester resin may be commercially available resins, and as an esterification reaction product of a polyacid and a polyalcohol, the polyacid and / or polyalcohol compound may contain unsaturated carbon bonds.

[0037] The above polycarboxylic acid may be, for example, a polycarboxylic acid, a polycarboxylic acid anhydride, a polycarboxylic acid halide, or a polycarboxylic acid ester. Specific examples of the above polycarboxylic acid may include maleic acid, maleic anhydride, fumaric acid, chloromaleic acid, ethyl maleic acid, itaconic acid, citraconic acid, xeronic acid, mesaconic acid, aconic acid, acetylene polycarboxylic acid, or mixtures thereof. Additionally, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, or mixtures thereof, which are commonly used in the manufacture of polyester resins, may be used, but are not limited thereto.

[0038] As the above polyhydric alcohol, dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol, trihydric alcohols such as glycerin, tetrahydric alcohols such as pentaerythritol, or mixtures thereof may be used. In addition, specific examples of unsaturated polyhydric alcohols may include butanediol, pentenediol, allyl or vinyl glycerol ether, allyl or vinyl pentaerythritol, or mixtures thereof.

[0039] The weight-average molecular weight of the above (D) unsaturated polyester resin is 2,000 g / mol to 100,000 g / mol, and may be, for example, 2,000 g / mol to 95,000 g / mol, 2,000 g / mol to 90,000 g / mol, 2,000 g / mol to 8,000 g / mol, or 2,000 g / mol to 7,000 g / mol. If the weight-average molecular weight of the above (D) unsaturated polyester resin is within the above range, the bonding strength of the components in the composition can be further increased, the moldability and processability of the composition are not reduced, and the appearance and texture of natural stone can be excellently realized.

[0040] A composition for engineered stone according to one embodiment may further include (E) an organic pigment or an inorganic pigment. An organic pigment or an inorganic pigment may be selected considering the durability, color clarity, and cost of the composition for engineered stone. A composition for engineered stone according to one embodiment may use (B) glass powder derived from waste glass as glass powder, in which case the color of the waste glass may be expressed as is, so additional pigments or dyes may not be required; however, if waste glass powder is not used or if the waste glass does not have the desired color, (E) an organic pigment or an inorganic pigment may be further included to achieve the desired color.

[0041] Examples of the above organic pigments include phthalocyanine blue, quinacridone, or azo pigments, and examples of inorganic pigments include titanium dioxide, iron oxide, chromium oxide, or ultramarine blue.

[0042] The above (E) organic pigment or inorganic pigment is included in an amount of 0.5% to 5% by weight based on the total weight of the composition for engineered stone according to one embodiment, and may be included, for example, in an amount of 0.5% to 4.5% by weight, 0.5% to 4.0% by weight, 0.5% to 3.5% by weight, 0.5% to 3.0% by weight, 1.0% to 4.5% by weight, or 1.0% to 4.0% by weight. When the (E) organic pigment or inorganic pigment is included in the above content range, the durability does not change, and the color of the composition can be maintained vividly for a long time.

[0043] In addition to the components of (A) to (E) above, the composition for engineered stone according to one embodiment may further use one or more additives to ensure flexural strength, impact strength, and excellent appearance while being eco-friendly, to adjust the balance between physical properties, or depending on the use of the engineered stone.

[0044] The above additives refer to one or more additives selected from, for example, curing agents, curing accelerators, crosslinking agents, leveling agents, ultraviolet absorbers, storage stabilizers, polymerization inhibitors, flame retardants, and antistatic agents, and these may be included alone or in combination of two or more.

[0045] The above additive may be appropriately used within a range that does not impair the physical properties of the above engineered stone composition, for example, it may be included in an amount of 10 parts by weight or less based on 100 parts by weight, which is the total amount of (A) to (E), and may be used in an amount of 1 to 8 parts by weight, for example, 1 to 5 parts by weight.

[0046] Another embodiment may provide an engineered stone manufactured from the aforementioned engineered stone composition. The engineered stone according to one embodiment contains crystalline silica in a lower amount than conventional engineered stone, thereby reducing the risk of causing silicosis.

[0047] The present invention will be explained in more detail below through examples and comparative examples, but the following examples and comparative examples are for illustrative purposes only and are not intended to limit the invention.

[0048]

[0049] Preparation and Evaluation of Compositions for Engineered Stone

[0050] The composition for engineered stone according to the examples and comparative examples is prepared by mixing the corresponding amounts of each component as shown in Table 1 below. In Table 1 below, the amounts of (A) to (E) are weight% based on the total weight of the composition.

[0051] Each of the above compositions was uniformly distributed using a dispensing device to maintain a consistent shape, then vacuum vibratory compression molded using a vacuum compression press, and subsequently placed in an oven to be cured at 120°C for 60 minutes to obtain a semi-finished product. Subsequently, the surface of the manufactured semi-finished product was polished with a grinder to produce engineered stone specimens with dimensions of 300 mm x 100 mm x 20 mm (width x height x thickness). The flexural strength of each engineered stone was measured according to ASTM D790-07E1. In addition, the content of crystalline silica contained in each engineered stone specimen was measured using XRD. The evaluation results are shown in Table 1 below, and the silica content refers to the weight percentage of crystalline silica relative to the total weight of the specimen.

[0052] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 Example 2 (a) Silica Sand 56------(A) Glass Sand-60 10 50 10 56 50 (B) Glass Powder-27 27 10 50 20 25 (C) Silica Powder 31-50 27 27 11 12 (D) Resin 12 12 12 12 12 12 12 (E) Pigment 11 11 11 Flexural Strength (MPa) 93.8 27.7 19.2 34.8 15.4 80.1 62.3 Silica Content (Weight%) 870 50 27 27 11 12

[0053] (A) Glass Sand

[0054] Glass sand from Hi Chipper, Inc. with an average particle size of 0.1 mm to 1.2 mm was used.

[0055] (a) Silica sand

[0056] Silica sand from Microman, with an average particle size of 0.1 mm to 1.2 mm, was used.

[0057] (B) Glass powder

[0058] Glass powder from Hi Chipper, Inc. with an average particle size of about 15㎛ (D50) was used.

[0059] (C) Silica powder

[0060] Silica powder from 21C Silica, with an average particle size of about 11㎛ (D50), was used.

[0061] (D) Unsaturated polyester resin

[0062] An unsaturated polyester resin (ATM-100) from Aekyung Chemical Co., Ltd. with a molecular weight of 2,500 g / mol was used.

[0063] (E) Organic pigment or inorganic pigment

[0064] I used 318M from Wooshin Pigment Co.

[0065]

[0066] Referring to Table 1 above, it was confirmed that flexural strength is relatively inferior when silica powder is not used or when a small amount of glass powder is used. Meanwhile, Comparative Example 1, which does not use (A) glass sand and (B) glass powder, has good flexural strength, but is harmful to the human body due to the high content of crystalline silica included in the composition. On the other hand, the composition for engineered stone according to the example had a low content of crystalline silica in the composition, yet both processability and flexural strength were excellent. In other words, it was confirmed that the engineered stone according to the example can perform the functions of conventional engineered stone better than that of the human body without being harmful to the human body.

[0067] Although the present invention has been described above through preferred embodiments as previously described, those skilled in the art will readily understand that the present invention is not limited thereto and that various modifications and variations are possible without departing from the concept and scope of the claims set forth below.

Claims

1. (A) 30% to 60% by weight of glass sand; (B) 20% to 40% by weight of glass powder; (C) 1% to 40% by weight of silica powder; and (D) A composition for engineered stone comprising 9% to 15% by weight of unsaturated polyester resin.

2. A composition for engineered stone according to claim 1, wherein the (C) silica powder is included in an amount of 1% to 25% by weight or less based on the total weight of the composition.

3. A composition for engineered stone according to claim 1 or 2, wherein the particle size of the (A) glass sand is 0.1 mm to 1.2 mm.

4. A composition for engineered stone, wherein, in any one of claims 1 to 3, the particle size of the (B) glass powder is 1 μm to 45 μm.

5. A composition for engineered stone, wherein, in any one of claims 1 to 4, the particle size of the (C) silica powder is 1 μm to 45 μm.

6. A composition for engineered stone, wherein, in any one of claims 1 to 5, the weight-average molecular weight of the (D) unsaturated polyester resin is 2,000 g / mol to 100,000 g / mol.

7. A composition for engineered stone, wherein, in any one of claims 1 to 6, the composition further comprises (E) an organic pigment or an inorganic pigment.

8. A composition for engineered stone according to claim 7, wherein the (E) organic pigment or inorganic pigment is included in an amount of 0.5% to 5% by weight based on the total weight of the composition.

9. A composition for engineered stone, wherein, in any one of claims 1 to 8, the composition further comprises one or more additives selected from a curing agent, a curing accelerator, a crosslinking agent, a leveling agent, a UV absorber, a storage stabilizer, an antipolymerization agent, a flame retardant, and an antistatic agent.

10. Engineered stone manufactured from a composition for engineered stone according to any one of claims 1 to 9.

11. In paragraph 10, the above engineered stone is an engineered stone having a flexural strength of 50 MPa to 95 MPa measured at 3 mm / min according to ASTM D790 on a specimen with width x length x thickness of 300 mm x 100 mm x 20 mm.