Artificial marble and its preparation method

Abstract

This application relates to the field of artificial stone technology, specifically to an artificial marble and its preparation method. The artificial marble of this application comprises the following components in parts by weight: 100 parts marble powder, 8-12 parts aliphatic polyisocyanate, 20-30 parts polypropylene glycol, 0.2-0.3 parts dibutyltin dilaurate, 10-15 parts cellulose ether modified magnesium lithium silicate, 5-7.5 parts polyvinyl acetate, and 2-3 parts flame retardant. This application uses aliphatic polyisocyanate to replace unsaturated polyester resin, reducing unsaturated double bonds in the system. Combined with cellulose ether modified magnesium lithium silicate and polyvinyl acetate, it improves the mechanical properties of the marble, thereby obtaining an artificial marble with excellent weather resistance, stain resistance, mechanical strength, and flame retardancy.

Description

Technical Field

[0001] This application relates to the field of artificial stone technology, and more specifically, to an artificial marble and a method for preparing the same. Background Technology

[0002] Artificial marble is a synthetic decorative material with advantages such as good gloss, bright and rich colors, strong workability, and good decorative effect. It is also cheaper than natural marble, so it is widely used in the field of building decoration.

[0003] Currently, organic artificial marble mainly uses natural marble as filler, unsaturated polyester resin and other curable materials as matrix, and then adds flame retardants and other additives to cure and form it together. However, common unsaturated polyester resins often do not react completely during curing, leaving unsaturated double bonds. With long-term use, especially under outdoor conditions, these bonds will oxidize, causing the organic artificial marble to discolor and turn yellow. It will also affect its mechanical properties, leading to problems such as cracking and warping. Summary of the Invention

[0004] To address the problems existing in the prior art, this application provides an artificial marble and its preparation method. The present invention uses aliphatic polyisocyanate to replace unsaturated polyester resin, reducing the number of unsaturated double bonds in the system. It also combines cellulose ether-modified magnesium lithium silicate and polyvinyl acetate to improve the mechanical properties of marble, thereby obtaining an artificial marble with excellent weather resistance, stain resistance, mechanical strength and flame retardancy.

[0005] In a first aspect, this application provides an artificial marble comprising the following components in parts by weight: 100 parts marble powder, 8-12 parts aliphatic polyisocyanate, 20-30 parts polypropylene glycol, 0.2-0.3 parts dibutyltin dilaurate, 10-15 parts cellulose ether modified magnesium lithium silicate, 5-7.5 parts polyvinyl acetate, and 2-3 parts flame retardant.

[0006] This application uses marble as a filler and utilizes the reaction of aliphatic polyisocyanate with polypropylene glycol to produce polyurethane. This polyurethane is not prone to yellowing and has excellent weather resistance. Dibutyltin dilaurate can significantly improve the reaction rate in the polyurethane synthesis process, specifically by interacting with isocyanate and hydroxyl reactants to reduce the activation energy of the reaction, thereby accelerating the reaction process.

[0007] However, dibutyltin dilaurate tends to precipitate into solids at low temperatures, affecting the color and appearance of artificial marble. Therefore, this application utilizes cellulose ether-modified lithium magnesium silicate. Lithium magnesium silicate is a trioctahedral layered silicate mineral. Because its thin-layer surfaces carry a negative charge and its end faces carry a positive charge, the separated end faces of the thin sheets are attracted to the surface of another thin sheet, thus rapidly forming a three-dimensional colloidal structure. This structure effectively adsorbs dibutyltin dilaurate, reducing its precipitation. The cellulose ether not only increases the compatibility of lithium magnesium silicate, polyurethane, and marble powder but also increases the hydroxyl content in its molecular structure. Furthermore, the aliphatic polyisocyanate in the system, under the influence of dibutyltin dilaurate, can combine with the cellulose ether-modified lithium magnesium silicate, thereby increasing the cross-linked network formed by the polyurethane, resulting in artificial marble with excellent mechanical strength.

[0008] Based on this, this application also adds an appropriate amount of polyvinyl acetate. Polyvinyl acetate has good compatibility with marble powder and cellulose ether modified magnesium lithium silicate. In this application, polyvinyl acetate can promote the uniform dispersion of marble powder, polyurethane and cellulose ether modified magnesium lithium silicate, and improve the film-forming properties of the system. On the other hand, the hydroxyl groups in polyvinyl acetate can also react with isocyanate groups to crosslink, further improving the weather resistance, stain resistance and mechanical strength of artificial marble.

[0009] Preferably, the weight ratio of the aliphatic polyisocyanate to the polypropylene glycol is 2:5.

[0010] Using the above technical solution, after the aliphatic polyisocyanate reacts with polypropylene glycol, there is still some residue. This excess aliphatic polyisocyanate can better combine with cellulose ether modified magnesium lithium silicate, thereby facilitating the effective formation of cross-linked networks in the system.

[0011] Preferably, the weight ratio of the cellulose ether modified magnesium lithium silicate to the aliphatic polyisocyanate is 6:5.

[0012] Using the above technical solution, if too much cellulose ether modified magnesium silicate is used, the viscosity of the system will increase, which will in turn increase the difficulty of dispersing marble powder and polyurethane; if too little cellulose ether modified magnesium silicate is used, it will be difficult to effectively lock dibutyltin dilaurate and marble powder; therefore, the amount of cellulose ether modified magnesium silicate in this application needs to be strictly controlled, and the above weight ratio is appropriate.

[0013] Preferably, the weight ratio of the cellulose ether modified magnesium lithium silicate to the polyvinyl acetate is 2:1.

[0014] If too much polyvinyl acetate is used in the above technical solution, it will affect the brittleness of the artificial marble to a certain extent. If too little polyvinyl acetate is used, it will be difficult to effectively play the dispersing role. The above weight ratio is preferred in this application.

[0015] Preferably, the preparation method of the cellulose ether modified magnesium lithium silicate includes the following steps: take an appropriate amount of water, first add cellulose ether and disperse it evenly, then add magnesium lithium silicate and continue to disperse it evenly, and then dry it to remove the moisture to obtain the cellulose ether modified magnesium lithium silicate.

[0016] Preferably, the weight ratio of the magnesium lithium silicate to the cellulose ether is 1:0.2-0.5.

[0017] This application utilizes water to uniformly disperse cellulose ether and lithium magnesium silicate. The operation is simple, the dispersion effect is good, and the subsequent water removal is also convenient. In this preparation method, the cellulose ether is dispersed first, which is conducive to the better coating of the cellulose ether on the surface of the lithium magnesium silicate molecules and improves the modification effect of the cellulose ether. The amount of cellulose ether needs to be strictly controlled. If the content of cellulose ether is too high, it will affect the water resistance of artificial marble. If the content of cellulose ether is too low, the modification effect of cellulose ether on lithium magnesium silicate will be poor, which will affect the dispersion effect of lithium magnesium silicate in the system.

[0018] Preferably, the cellulose ether is a mixture of hydroxyethyl cellulose 250HBR and hydroxyethyl cellulose 250HHBR.

[0019] Preferably, the weight ratio of the hydroxyethyl cellulose 250HBR to the hydroxyethyl cellulose 250HHBR is 1:1.

[0020] In this application, the cellulose ether-modified magnesium silicate lithium cellulose ether can also coat the color spots in marble powder, thereby ensuring the vibrant color of the artificial marble. However, different cellulose ethers have significantly different molecular structures, which greatly affect the morphology and stability of the color spots in the marble powder. For example, with hydroxyethyl cellulose 250HBR, the color spots are easily broken when added in small amounts, but when a certain amount is reached, the color spots are not easily broken, but the artificial marble prepared from it is brittle. On the other hand, with the same amount of hydroxyethyl cellulose 250HBR, the color spots are not easily broken, and the artificial marble prepared from it is less brittle, but when the amount exceeds a certain level, the brittleness of the artificial marble also increases. This may be due to the difference in relative molecular mass between the two. The average relative molecular weight of 250HBR is 30,000, and the molecular chain is relatively short. When used in small amounts, the color spots are easily broken, but when used in larger amounts, due to the greater number of cross-linking points with magnesium silicate, the subsequent brittleness is greater. 250HHBR has an average relative molecular weight of 100,000 and a relatively long molecular chain. With appropriate dosage, a balance can be achieved between encapsulation and cross-linking with lithium magnesium silicate, resulting in artificial marble with less brittleness and less color breakage. Therefore, this application, by strictly controlling the type and dosage of cellulose ether, enables the obtained cellulose ether-modified lithium magnesium silicate to not only effectively maintain the color stability of artificial marble but also further improve its mechanical strength.

[0021] Preferably, the flame retardant is a silicon-based flame retardant.

[0022] Silicon-based flame retardants have the characteristics of high efficiency, low toxicity, anti-dripping, easy charring, and smoke suppression. They include siloxanes, inorganic silicon-based flame retardants, and organic-inorganic hybrid silicon-based flame retardants. In this application, the above-mentioned silicon-based flame retardants can be well dispersed in the system to effectively exert the flame retardant effect.

[0023] Secondly, this application provides a method for preparing artificial marble, comprising the following steps:

[0024] The marble powder, polypropylene glycol, cellulose ether modified magnesium lithium silicate, and polyvinyl acetate are first mixed in a predetermined amount to obtain a mixture.

[0025] Add the set amount of aliphatic polyisocyanate and flame retardant to the mixture and continue mixing. Then add dibutyltin dilaurate and stir thoroughly to obtain the pre-cured material.

[0026] The pre-cured material is put into a mold and pressed into shape. After heat curing and cooling, the artificial marble is obtained.

[0027] Both cellulose ether-modified magnesium lithium silicate and polyvinyl acetate have a certain degree of hydrophilicity. In this application, cellulose ether-modified magnesium lithium silicate, polyvinyl acetate and marble powder are first evenly dispersed with polypropylene glycol. Compared with directly adding marble powder to aliphatic polyisocyanate, this can effectively reduce agglomeration. Then, aliphatic polyisocyanate is added and mixed. At this time, the reaction is slow due to the lack of catalyst in the system, which helps the components to be fully dispersed first. Finally, the catalyst is added to accelerate the formation of polyurethane. The artificial marble obtained in this way has better colorfastness, weather resistance and mechanical strength.

[0028] In summary, this application has the following beneficial effects:

[0029] 1. This application uses aliphatic polyisocyanate to replace unsaturated polyester resin, and uses cellulose ether modified magnesium lithium silicate and polyvinyl acetate, which can not only effectively slow down the yellowing of artificial marble due to oxidation, but also has excellent weather resistance, stain resistance, mechanical strength and flame retardancy.

[0030] 2. This application maintains the reaction parameters of the system in a dynamic equilibrium state by strictly controlling the weight ratio of aliphatic polyisocyanate to polypropylene glycol, cellulose ether modified magnesium lithium silicate, and polyvinyl acetate, thereby further improving the weather resistance, stain resistance, and mechanical strength of artificial marble.

[0031] 3. This application further limits the cellulose ether-modified magnesium lithium silicate, thereby enabling artificial marble to have superior weather resistance and mechanical strength.

[0032] 4. In the preparation of artificial marble, this application ensures that each component is fully dispersed by strictly controlling the order of component addition, thereby obtaining artificial marble with superior weather resistance and mechanical strength. Detailed Implementation

[0033] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0034] All raw materials used in this application are commercially available products. The marble powder is 400 mesh; the aliphatic polyisocyanate is a Rhodia product. Taking X FD 90 B as an example for illustration, its average relative molecular weight is 666 and its purity is 99%; the CAS number of polypropylene glycol is 25322-69-4, and its average molecular weight is 2025; the CAS number of dibutyltin dilaurate is 77-58-7 and its purity is 95%; taking the product with Shanghai Aladdin product number P304876 as an example for polyvinyl acetate, its CAS number is 9003-20-7, it is a light yellow transparent glassy particle, and the content of the active ingredient is 99%; taking methylphenyl polysiloxane, diphenyldimethyl polysiloxane and tris(isopropylphenyl) phosphate (IPPP50) as examples for the flame retardant; taking hydroxyethyl cellulose 250HBR, hydroxyethyl cellulose 250HHBR and methyl cellulose (350-550 MPA·S, 2% aqueous solution at 20 °C) as examples for the cellulose ether; the CAS number of lithium magnesium silicate is 37220-90-9, its purity is 99%, and its dispersion viscosity (5% solid content) is 3000 cps.

[0035] Preparation Example of Cellulose Ether Modified Lithium Magnesium Silicate

[0036] Preparation Example 1

[0037] This preparation example provides a preparation method of cellulose ether modified lithium magnesium silicate, which includes the following steps: Take 200 g of water, first add 20 g of hydroxyethyl cellulose 250HBR and 20 g of hydroxyethyl cellulose 250HHBR and disperse them evenly, then add 100 g of lithium magnesium silicate and continue to disperse evenly, and then obtain it after drying to remove water, denoted as cellulose ether modified lithium magnesium silicate a.

[0038] Preparation Example 2

[0039] This preparation example provides a preparation method of cellulose ether modified lithium magnesium silicate, which includes the following steps: Take 200 g of water, first add 5 g of hydroxyethyl cellulose 250HBR and 5 g of hydroxyethyl cellulose 250HHBR and disperse them evenly, then add 100 g of lithium magnesium silicate and continue to disperse evenly, and then obtain it after drying to remove water, denoted as cellulose ether modified lithium magnesium silicate b.

[0040] Preparation Example 3

[0041] This preparation example provides a preparation method of cellulose ether modified lithium magnesium silicate, which includes the following steps: Take 200 g of water, first add 10 g of hydroxyethyl cellulose 250HBR and 10 g of hydroxyethyl cellulose 250HHBR and disperse them evenly, then add 100 g of lithium magnesium silicate and continue to disperse evenly, and then obtain it after drying to remove water, denoted as cellulose ether modified lithium magnesium silicate c.

[0042] Preparation Example 4

[0043] This preparation example provides a method for preparing cellulose ether modified magnesium lithium silicate, including the following steps: Take 200g of water, first add 25g of hydroxyethyl cellulose 250HBR and 25g of hydroxyethyl cellulose 250HHBR and disperse evenly, then add 100g of magnesium lithium silicate and continue to disperse evenly, and then dry to remove moisture to obtain the cellulose ether modified magnesium lithium silicate, denoted as d.

[0044] Preparation Example 5

[0045] This preparation example provides a method for preparing cellulose ether modified magnesium lithium silicate, including the following steps: take 200g of water, first add 30g of hydroxyethyl cellulose 250HBR and 30g of hydroxyethyl cellulose 250HHBR and disperse evenly, then add 100g of magnesium lithium silicate and continue to disperse evenly, and then dry to remove moisture to obtain the product, denoted as cellulose ether modified magnesium lithium silicate e.

[0046] Preparation Example 6

[0047] This preparation example provides a method for preparing cellulose ether modified magnesium lithium silicate, including the following steps: Take 200g of water, first add 10g of hydroxyethyl cellulose 250HBR and 30g of hydroxyethyl cellulose 250HHBR and disperse evenly, then add 100g of magnesium lithium silicate and continue to disperse evenly, and then dry to remove moisture to obtain the product, denoted as cellulose ether modified magnesium lithium silicate f.

[0048] Preparation Example 7

[0049] This preparation example provides a method for preparing cellulose ether modified magnesium lithium silicate, including the following steps: Take 200g of water, first add 30g of hydroxyethyl cellulose 250HBR and 10g of hydroxyethyl cellulose 250HHBR and disperse evenly, then add 100g of magnesium lithium silicate and continue to disperse evenly, and then dry to remove moisture to obtain the cellulose ether modified magnesium lithium silicate (g).

[0050] Preparation Example 8

[0051] This preparation example provides a method for preparing cellulose ether modified magnesium lithium silicate, including the following steps: take 200g of water, first add 20g of methylcellulose and 20g of hydroxyethylcellulose 250HHBR and disperse evenly, then add 100g of magnesium lithium silicate and continue to disperse evenly, and then dry to remove moisture to obtain the product, denoted as cellulose ether modified magnesium lithium silicate h.

[0052] Preparation Example 9

[0053] This preparation example provides a method for preparing cellulose ether modified magnesium lithium silicate, including the following steps: take 200g of water, first add 40g of hydroxyethyl cellulose 250HHBR and disperse evenly, then add 100g of magnesium lithium silicate and continue to disperse evenly, and then dry to remove moisture to obtain the product, denoted as cellulose ether modified magnesium lithium silicate i.

[0054] Preparation Example 10

[0055] This preparation example provides a method for preparing cellulose ether modified magnesium lithium silicate, including the following steps: take 200g of water, first add 40g of hydroxyethyl cellulose 250HBR and disperse evenly, then add 100g of magnesium lithium silicate and continue to disperse evenly, and then dry to remove moisture to obtain the product, denoted as cellulose ether modified magnesium lithium silicate i.

[0056] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0057] Example

[0058] Example 1

[0059] This embodiment provides a method for preparing artificial marble, including the following steps:

[0060] ① First, mix 1000g of marble powder, 250g of polypropylene glycol, 120g of cellulose ether modified magnesium lithium silicate a with 60g of polyvinyl acetate to obtain a mixture.

[0061] ② Add 100g of aliphatic polyisocyanate and 25g of methylphenyl polysiloxane to the mixture and continue mixing. Then add 2.5g of dibutyltin dilaurate and stir thoroughly to obtain the pre-cured material.

[0062] ③ Pour the pre-cured material into the mold and press it into shape. Keep it at 90℃ for 30 minutes to cure. After curing, cool and demold to obtain artificial marble.

[0063] Examples 2-4

[0064] Examples 2-4 are based on the method of Example 1, with adjustments made to the amount of components. See Table 1 below for details of the adjustments.

[0065] Table 1. Component dosage for Examples 1-4 (unit: g)

[0066]

[0067]

[0068] Examples 5-6

[0069] Examples 5-6 are based on the method of Example 1, but with adjustments made to the weight ratio of aliphatic polyisocyanate and polypropylene glycol. For details of the adjustments, please refer to Table 1 above.

[0070] Examples 7-8

[0071] Examples 7-8 are based on the method of Example 1, but with adjustments made to the weight ratio of cellulose ether modified magnesium lithium silicate to aliphatic polyisocyanate. For details of the adjustments, please refer to Table 1 above.

[0072] Examples 9-10

[0073] Examples 9-10 are based on the method of Example 1, but with adjustments made to the weight ratio of cellulose ether-modified magnesium lithium silicate to polyvinyl acetate. For details of the adjustments, please refer to Table 1 above.

[0074] Examples 11-19

[0075] Examples 11-19 are based on the method of Example 1, but with the cellulose ether modified magnesium lithium silicate a replaced. Specifically, Example 11 uses cellulose ether modified magnesium lithium silicate b prepared in Preparation Example 2; Example 12 uses cellulose ether modified magnesium lithium silicate c prepared in Preparation Example 3; Example 13 uses cellulose ether modified magnesium lithium silicate d prepared in Preparation Example 4; Example 14 uses cellulose ether modified magnesium lithium silicate e prepared in Preparation Example 5; Example 15 uses cellulose ether modified magnesium lithium silicate f prepared in Preparation Example 6; Example 16 uses cellulose ether modified magnesium lithium silicate g prepared in Preparation Example 7; Example 17 uses cellulose ether modified magnesium lithium silicate h prepared in Preparation Example 8; Example 18 uses cellulose ether modified magnesium lithium silicate i prepared in Preparation Example 9; and Example 19 uses cellulose ether modified magnesium lithium silicate j prepared in Preparation Example 10.

[0076] Examples 20-21

[0077] Examples 20-21 are based on the method of Example 1, but with the flame retardant methylphenyl polysiloxane replaced. Specifically, the flame retardant used in Example 20 is diphenyldimethylpolysiloxane; and the flame retardant used in Example 21 is triisopropylphenyl phosphate.

[0078] Example 22

[0079] Example 22 is based on the component formulation of Example 1, with adjustments made to the preparation method, specifically including the following steps:

[0080] ① First, mix 1000g marble powder, 100g aliphatic polyisocyanate, 350g polypropylene glycol, 2.5g dibutyltin dilaurate and 25g methylphenyl polysiloxane to obtain a mixture.

[0081] ② Add 120g of cellulose ether modified magnesium lithium silicate a and 60g of polyvinyl acetate to the mixture and continue to mix to obtain the pre-cured material;

[0082] ③ Pour the pre-cured material into the mold and press it into shape. Keep it at 90℃ for 30 minutes to cure. After curing, cool and demold to obtain artificial marble.

[0083] Comparative Example

[0084] Comparative Example 1

[0085] This comparative example is based on the method of Example 1, but uses an equal amount of lithium magnesium silicate to replace the cellulose ether-modified lithium magnesium silicate a.

[0086] Comparative Example 2

[0087] This comparative example is based on the method of Example 1, but uses a mixture of 20g hydroxyethyl cellulose 250HBR, 20g hydroxyethyl cellulose 250HHBR and 100g magnesium silicate to replace the cellulose ether modified magnesium silicate a.

[0088] Comparative Example 3

[0089] This comparative example is based on the method of Example 1, but uses an equal amount of polyvinyl acetate to replace cellulose ether-modified lithium magnesium silicate a.

[0090] Comparative Example 4

[0091] This comparative example is based on the method of Example 1, but uses an equal amount of cellulose ether-modified magnesium lithium silicate a to replace polyvinyl acetate.

[0092] Comparative Example 5

[0093] This comparative example provides a method for preparing artificial marble, including the following steps:

[0094] ① First, mix 1000g of marble powder, 120g of cellulose ether modified magnesium lithium silicate a with 60g of polyvinyl acetate to obtain a mixture.

[0095] ② Add 452.5g of bisphenol A type unsaturated polyester resin (model 3301C) and 25g of methylphenyl polysiloxane to the mixture and continue mixing to obtain the pre-cured material;

[0096] ③ Pour the pre-cured material into the mold and press it into shape. Keep it at 90℃ for 30 minutes to cure. After curing, cool and demold to obtain artificial marble.

[0097] Performance testing

[0098] The artificial marbles prepared in Examples 1-22 and Comparative Examples 1-5 of this application were used as samples, and the following performance tests were conducted. The test results are shown in Table 2 below.

[0099] 1. Weather resistance: The gloss retention rate of the sample before and after UV aging treatment is used to illustrate the performance. This gloss is specular gloss, with an incident angle of 60°. The UV aging treatment of the sample specifically refers to standard GB / T 16422.3-2014, using a type 1A (UVA-340) fluorescent UV lamp, with an exposure cycle of 8 hours of drying + 4 hours of condensation, and an irradiance of 0.76 W / m at 340 nm. 2 / nm, radiation temperature is 60±3℃;

[0100] 2. Stain resistance: Immerse the sample in a mixture of water and cooking oil in a 1:1 ratio for 48 hours, then remove it and observe whether there are any stains on the sample surface.

[0101] 3. Mechanical strength: illustrated with physical and mechanical properties, refer to standard DB44 / T768-2010 "Resin-based Artificial Stone Slabs" for details;

[0102] 4. Flame retardant properties: illustrated using limiting oxygen index and comparative combustion characteristics of solid plastics in a vertical position, with reference to standards ASTM D-2836 and ASTM D-3801.

[0103] Table 2 Performance test results of Examples 1-22 and Comparative Examples 1-5

[0104]

[0105]

[0106] Referring to Table 2, and combining the test results of Examples 1 to 4 and Comparative Examples 1 to 5, it can be seen that the present application uses aliphatic polyisocyanate to replace unsaturated polyester resin, and uses cellulose ether modified magnesium lithium silicate and polyvinyl acetate in combination. Moreover, the cellulose ether modified magnesium lithium silicate and polyvinyl acetate cannot be arbitrarily replaced. The artificial marble produced in this way has excellent weather resistance, stain resistance, mechanical strength and flame retardancy.

[0107] Comparing the test results of Examples 1 with those of Examples 5 to 10, it can be seen that the uniform adjustment of the amounts of aliphatic polyisocyanate, polypropylene glycol, cellulose ether modified magnesium silicate lithium, and polyvinyl acetate in this application affects the performance of artificial marble. In this application, when the weight ratio of aliphatic polyisocyanate to polypropylene glycol is strictly controlled to be 2:7, the weight ratio of cellulose ether modified magnesium silicate lithium to aliphatic polyisocyanate to be 6:5, and the weight ratio of cellulose ether modified magnesium silicate lithium to polyvinyl acetate to be 2:1, the artificial marble obtained has higher gloss retention, compressive strength, flexural strength, and limiting oxygen index. In addition, its stain resistance is also better. Therefore, it is considered a further preferred option.

[0108] Comparing the test results of Example 1 with those of Examples 11 to 19, it can be seen that when the weight ratio of magnesium silicate to cellulose ether in the cellulose ether modified magnesium lithium silicate used in this application is 1:0.2-0.5, and the cellulose ether is compounded from hydroxyethyl cellulose 250HBR and hydroxyethyl cellulose 250HHBR in a weight ratio of 1:1, the resulting artificial marble has a higher gloss retention rate and better stain resistance and mechanical properties.

[0109] Comparing the test results of Example 1 with those of Examples 20 and 21, it can be seen that the silicon-based flame retardant used in this application has better flame retardant performance than other flame retardants. Methylphenyl polysiloxane is further preferred, possibly because methylphenyl polysiloxane has a relatively small molecular weight, which can achieve uniform dispersion and rapidly migrate to the surface of artificial marble for flame retardancy during combustion. Therefore, it is preferred.

[0110] Comparing the test results of Example 1 and Example 22, it can be seen that the different order of component addition during the preparation of artificial marble can affect the performance of artificial marble to a certain extent. Therefore, this application ensures that each component is fully dispersed by strictly controlling the order of component addition, thereby obtaining artificial marble with better weather resistance and mechanical strength.

[0111] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An artificial marble, characterized by, The composition comprises the following components by weight: marble powder 100 parts, aliphatic polyisocyanate 8-12 parts, polypropylene glycol 20-30 parts, dibutyltin dilaurate 0.2-0.3 parts, cellulose ether modified magnesium lithium silicate 10-15 parts, polyvinyl acetate 5-7.5 parts, and flame retardant 2-3 parts.

2. The artificial marble according to claim 1, characterized in that: The weight ratio of the aliphatic polyisocyanate to the polypropylene glycol is 2:

5.

3. The artificial marble according to claim 1, characterized in that: The weight ratio of the cellulose ether modified magnesium lithium silicate to the aliphatic polyisocyanate is 6:

5.

4. The artificial marble according to claim 1, characterized in that: The weight ratio of the cellulose ether modified magnesium lithium silicate to the polyvinyl acetate is 2:

1.

5. The artificial marble according to claim 1, characterized in that: The preparation method of the cellulose ether modified magnesium lithium silicate comprises the following steps: taking a proper amount of water, first adding cellulose ether and dispersing uniformly, then adding magnesium lithium silicate and dispersing uniformly, and then drying to remove water to obtain the cellulose ether modified magnesium lithium silicate.

6. The artificial marble according to claim 5, characterized in that: The weight ratio of the magnesium lithium silicate to the cellulose ether is 1:0.2-0.

5.

7. The artificial marble according to claim 1, characterized in that: The cellulose ether is a mixture of hydroxyethyl cellulose 250HBR and hydroxyethyl cellulose 250HHBR.

8. The artificial marble according to claim 7, characterized in that: The weight ratio of the hydroxyethyl cellulose 250HBR to the hydroxyethyl cellulose 250HHBR is 1:

1.

9. The artificial marble according to claim 1, characterized in that: The flame retardant is a silicon-based flame retardant.

10. Process for the preparation of the artificial marble according to any one of claims 1-9, characterized in that, The method comprises the following steps: A certain amount of marble powder, polypropylene glycol, cellulose ether modified magnesium lithium silicate, and polyvinyl acetate are preliminarily mixed to obtain a mixture; A certain amount of aliphatic polyisocyanate and flame retardant are added to the mixture and mixed again, and then dibutyltin dilaurate is added and stirred fully to obtain a pre-cured material; The pre-cured material is pressed into a mold for molding, and then the mold is cooled and demolded after heat curing, thereby obtaining the artificial marble.

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