A lightweight artificial granite plate and its preparation process

Abstract

The present invention discloses a lightweight artificial granite plate and its preparation process, belonging to the technical field of plate preparation, which includes the following steps: S1, pre-treat the substrate; S2, spray a bottom layer slurry on the pre-treated substrate; S3, spray a pattern layer slurry and a transparent protective layer slurry on the bottom layer slurry; S4, perform step-by-step curing on the sprayed plate, and perform surface treatment on the cured plate to obtain a lightweight artificial granite plate. Through the synergistic effect of substrate pre-treatment, biomass-modified phenolic prepolymer and modified hollow ceramic microspheres, the present invention prepares an artificial granite plate with both lightweight, high strength and excellent durability.

Description

Technical Field

[0001] The present invention relates to the technical field of sheet material preparation, and particularly relates to a lightweight artificial granite sheet and a preparation process thereof. Background Art

[0002] As an important building decoration material, granite sheets are widely used in various occasions such as the interior and exterior walls, floors, and countertops of buildings due to their hard texture, beautiful color, and good wear resistance. At present, the granite sheets used in the market are mainly divided into two categories: natural granite and artificial granite.

[0003] Natural granite is an igneous rock composed of minerals such as quartz, feldspar, and mica. It is mined from natural mines and processed through processes such as cutting and polishing. However, natural granite has problems such as high density, excessive self-weight, limited resources, and environmental damage during the mining process. In addition, although natural granite has a relatively high hardness, it is relatively brittle and has limited flexural strength, and is prone to fracture in specific application scenarios. Summary of the Invention

[0004] The present invention discloses a lightweight artificial granite sheet and a preparation process thereof, solving the technical problems of high density, brittleness, and limited flexural strength of natural granite sheets in the prior art.

[0005] The preparation process of the lightweight artificial granite sheet disclosed by the present invention includes the following steps:

[0006] S1. Pretreat the substrate;

[0007] S2. Spray a bottom layer slurry on the pretreated substrate;

[0008] S3. Spray a pattern layer slurry and a transparent protective layer slurry on the bottom layer slurry;

[0009] S4. Cure the sprayed sheet step by step, and perform surface treatment on the cured sheet to obtain a lightweight artificial granite sheet.

[0010] Preferably, the bottom layer slurry is composed of the following components: 40-50 parts of unsaturated polyester resin, 15-20 parts of biomass-modified phenolic prepolymer, 20-25 parts of modified hollow ceramic microspheres, 2-4 parts of nano-silica, and 1-3 parts of curing agent.

[0011] Preferably, the preparation method of the modified hollow ceramic microspheres is: drying the hollow ceramic microspheres at 100-110 °C for 10-14 hours, putting them into a 95% ethanol solution of KH-550 and stirring for 1.5-2.5 hours, filtering and drying at 70-85 °C for 3-5 hours to obtain modified hollow ceramic microspheres.

[0012] Preferably, the preparation method of the biomass-modified phenolic prepolymer is as follows: Mix enzymatic lignin and phenol in a mass ratio of 1:5, add a formaldehyde solution with a concentration of 37 wt%, under the condition of pH = 9.3 - 9.7, control the reaction temperature at 83 - 87 °C, react for 2 - 3 hours, after cooling to 25 °C, adjust the pH to 6.5 - 7.0 with dilute hydrochloric acid, and remove water by vacuum rotary evaporation to obtain the biomass-modified phenolic prepolymer.

[0013] Preferably, the dosage of KH-550 is 2% - 3% wt of the hollow ceramic microspheres.

[0014] Preferably, the molar ratio of phenol to formaldehyde is 1:1.8.

[0015] Preferably, the spraying process parameters in step S2 are: the spraying pressure is 0.32 - 0.38 MPa, the spraying distance is 23 - 27 cm, and the thickness is 1.1 - 1.3 mm.

[0016] Preferably, the unsaturated polyester resin is an orthophthalic unsaturated polyester resin, and the molecular weight range is 2200 - 2800 g / mol.

[0017] Preferably, the substrate pretreatment in step S1 includes:

[0018] Select granite plates as the substrate, use a high-pressure air gun to remove surface dust, wipe and degrease the surface with isopropanol, dry at room temperature for 20 - 40 minutes, coat the primer, the primer coating amount is 140 - 160 g / m², and pre-dry at 55 - 65 °C for 40 - 50 minutes.

[0019] The present invention also provides a lightweight artificial granite plate prepared by the above preparation process.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] (1) The density of the lightweight artificial granite plate prepared by the present invention is 1945 - 2010 kg / m³, which is significantly lower than that of natural granite. At the same time, the flexural strength reaches 27.2 - 29.6 MPa, which is 80% - 97% higher than that of natural granite, realizing the improvement of the strength of granite plates while reducing the density.

[0022] (2) The water absorption rate of the plate prepared by the present invention is lower than that of natural granite, indicating that the material has excellent stability in a humid environment; in the freeze-thaw resistance performance test, the strength loss rate is only 2.2% - 2.8%, close to that of natural granite.

[0023] (3) By using KH-550 to modify the surface of hollow ceramic microspheres, the compatibility between the slurry and the microspheres at the interface is significantly enhanced, effectively improving the overall performance and structural stability of the composite material.

[0024] (4) By mixing enzymatically hydrolyzed lignin with phenol to prepare a modified phenolic prepolymer, the present invention not only realizes the high-value utilization of biomass resources, but also significantly improves the toughness and environmental resistance of the material.

[0025] In summary, through the synergistic effect of substrate pretreatment, biomass-modified phenolic prepolymer and modified hollow ceramic microspheres, the present invention prepares artificial granite plates with light weight, high strength and excellent durability. Specific Embodiments

[0026] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] The granite plates used in this embodiment are commercially available standard building granite plates, with a specification of 600mm×300mm×15mm, a type of fine-grained grayish-white granite. The surface of the plate has been processed by standard mechanical polishing, and the flatness error is controlled within ±0.5mm. The edges have been chamfered to avoid sharp edges, the density is about 2650kg / m³, and the compressive strength is about 180MPa; the unsaturated polyester resin used is o-phthalic unsaturated polyester resin, and the molecular weight range is 2200-2800g / mol;

[0028] The pattern layer slurry used in the embodiments of the present application is composed of the following components: o-phthalic unsaturated polyester resin: 40 parts; iron oxide-based pigment: 12 parts; granite powder: 25 parts; mica powder: 8 parts; titanium dioxide: 5 parts; fumed silica thickener: 2 parts; polycarboxylate dispersant: 1.5 parts; methyl ethyl ketone peroxide curing agent: 1.8 parts; cobalt octoate accelerator: 0.6 parts. The pattern layer spraying process is that the spraying pressure is 0.30MPa, the spraying distance is 20cm, and the thickness is 0.8mm; the enzymatically hydrolyzed lignin used is from Shandong Longli Biotechnology Co., Ltd., and is corn straw enzymatically hydrolyzed lignin; the curing agent used is from Jiangsu Sanmu Group Co., Ltd., and the model is M-50.

[0029] The transparent protective layer slurry used in the embodiments of the present application is composed of the following components: methyl methacrylate modified unsaturated polyester resin: 55 parts; nano-silica: 4 parts; hydroxybenzotriazole ultraviolet absorber: 2 parts; hindered phenol antioxidant: 1.5 parts; polysiloxane leveling agent: 1 part; di-tert-butyl peroxide curing agent: 2.5 parts; polyvinyl butyral low shrinkage agent: 3 parts. The spraying process parameters of the transparent protective layer slurry are as follows: spraying pressure is 0.30 MPa, spraying distance is 20 cm, and thickness is 0.6 mm.

[0030] Example 1

[0031] This example provides a preparation process for lightweight artificial granite plates.

[0032] S1. Using a granite plate as the substrate, use a high-pressure air gun to remove surface dust at an air pressure of 0.5 MPa, and then wipe and degrease the surface of the substrate with isopropyl alcohol and dry it at 25 °C for 30 minutes.

[0033] S2. Coating the primer, the primer coating amount is 150 g / m², and pre-drying at 60 °C for 45 minutes to complete the pretreatment of the substrate.

[0034] S3. Spraying the bottom layer slurry on the pretreated substrate. The bottom layer slurry is composed of the following components: orthophthalic unsaturated polyester resin 45 parts, biomass modified phenolic prepolymer 18 parts, modified hollow ceramic microspheres 22 parts, nano-silica 3 parts, curing agent 2 parts.

[0035] Among them, the preparation method of the biomass modified phenolic prepolymer is as follows: Mix enzymatic lignin and phenol in a mass ratio of 1:5, add a formaldehyde solution with a concentration of 37 wt%, the molar ratio of phenol to formaldehyde is 1:1.8, under the condition of pH = 9.5, control the reaction temperature at 85 °C, react for 2.5 hours, cool down to 25 °C, and then adjust the pH to 6.8 with dilute hydrochloric acid, and remove moisture by vacuum rotary evaporation to obtain the biomass modified phenolic prepolymer.

[0036] The preparation method of the modified hollow ceramic microspheres is as follows: Dry the hollow ceramic microspheres at 105 °C for 12 hours, put them into a 95% ethanol solution of KH-550 and stir for 2 hours, the dosage of KH-550 is 2.5%wt of the hollow ceramic microspheres, filter and dry at 80 °C for 4 hours to obtain the modified hollow ceramic microspheres.

[0037] The spraying process parameters of the bottom layer slurry are as follows: spraying pressure 0.35 MPa, spraying distance 25 cm, thickness 1.2 mm.

[0038] S4. Spray the pattern layer slurry and the transparent protective layer slurry on the bottom layer slurry in sequence, and then perform stepwise curing on the sprayed plate. The curing temperature is first maintained at 60 °C for 1 hour, then at 80 °C for 2 hours, and finally at 120 °C for 0.5 hour. The cured plate is subjected to surface treatment, including sanding and polishing, to obtain a lightweight artificial granite plate.

[0039] Example 2

[0040] This example provides a preparation process for a lightweight artificial granite plate.

[0041] S1. Use a granite plate as the substrate, and use a high-pressure air gun to remove surface dust at an air pressure of 0.6 MPa. Subsequently, wipe and degrease the surface of the substrate with isopropanol and dry it at 24 °C for 25 minutes.

[0042] S2. Coat the primer with a coating amount of 145 g / m², and pre-dry it at a temperature of 58 °C for 42 minutes to complete the pretreatment of the substrate.

[0043] S3. Spray the bottom layer slurry on the pretreated substrate. The bottom layer slurry consists of the following components: 40 parts of o-phthalic unsaturated polyester resin, 15 parts of biomass-modified phenolic prepolymer, 25 parts of modified hollow ceramic microspheres, 4 parts of nano-silica, and 3 parts of curing agent.

[0044] Among them, the preparation method of the biomass-modified phenolic prepolymer is as follows: Mix enzymatically hydrolyzed lignin and phenol in a mass ratio of 1:5, add a formaldehyde solution with a concentration of 37 wt%, the molar ratio of phenol to formaldehyde is 1:1.8, control the reaction temperature at 83 °C under the condition of pH = 9.3, react for 2 hours, cool down to 25 °C, and then adjust the pH to 7.0 with dilute hydrochloric acid, and remove water by vacuum rotary evaporation to obtain the biomass-modified phenolic prepolymer.

[0045] The preparation method of the modified hollow ceramic microspheres is as follows: Dry the hollow ceramic microspheres at 100 °C for 10 hours, put them into a 95% ethanol solution of KH-550 and stir for 1.5 hours. The dosage of KH-550 is 2.0% wt of the hollow ceramic microspheres. After filtration, dry at 70 °C for 3 hours to obtain the modified hollow ceramic microspheres.

[0046] The spraying process parameters of the bottom layer slurry are: spraying pressure 0.32 MPa, spraying distance 23 cm, and thickness 1.1 mm.

[0047] S4. Spray the pattern layer slurry and the transparent protective layer slurry on the bottom layer slurry in sequence, and then perform stepwise curing on the sprayed plate. The curing temperature is first maintained at 55 °C for 1.5 hours, then at 75 °C for 2.5 hours, and finally at 115 °C for 0.8 hour. The cured plate is subjected to surface treatment, including sanding and polishing, to obtain a lightweight artificial granite plate.

[0048] Example 3

[0049] This example provides a preparation process for lightweight artificial granite plates.

[0050] S1. Using a granite plate as the substrate, use a high-pressure air gun to remove surface dust at an air pressure of 0.55 MPa. Subsequently, wipe and degrease the substrate surface with isopropanol and dry it at 26 °C for 40 minutes.

[0051] S2. Coat the primer with a coating amount of 160 g / m² and pre-dry it at 65 °C for 50 minutes to complete the pretreatment of the substrate.

[0052] S3. Spray the bottom layer slurry on the pretreated substrate. The bottom layer slurry is composed of the following components: 50 parts of o-phthalic unsaturated polyester resin, 20 parts of biomass-modified phenolic prepolymer, 20 parts of modified hollow ceramic microspheres, 2 parts of nano-silica, and 1 part of curing agent.

[0053] Among them, the preparation method of the biomass-modified phenolic prepolymer is as follows: Mix enzymatic lignin and phenol in a mass ratio of 1:5, add a formaldehyde solution with a concentration of 37 wt%, the molar ratio of phenol to formaldehyde is 1:1.8, control the reaction temperature at 87 °C under the condition of pH = 9.7, react for 3 hours, cool down to 25 °C, and then adjust the pH to 6.5 with dilute hydrochloric acid, and remove moisture by vacuum rotary evaporation to obtain the biomass-modified phenolic prepolymer.

[0054] The preparation method of the modified hollow ceramic microspheres is as follows: Dry the hollow ceramic microspheres at 110 °C for 14 hours, put them into a 95% ethanol solution of KH-550 and stir for 2.5 hours. The dosage of KH-550 is 3.0% wt of the hollow ceramic microspheres. After filtration, dry them at 85 °C for 5 hours to obtain the modified hollow ceramic microspheres.

[0055] The spraying process parameters of the bottom layer slurry are: spraying pressure 0.38 MPa, spraying distance 27 cm, and thickness 1.3 mm.

[0056] S4. Spray the pattern layer slurry and the transparent protective layer slurry on the bottom layer slurry in sequence, and then cure the sprayed plate step by step. The curing temperature is first maintained at 65 °C for 1.2 hours, then at 85 °C for 1.8 hours, and finally at 125 °C for 0.6 hours. The cured plate is subjected to surface treatment, including sanding and polishing, to obtain the lightweight artificial granite plate.

[0057] Example 4

[0058] This example provides a preparation process for lightweight artificial granite plates.

[0059] S1. Use a granite plate as the substrate, and use a high-pressure air gun to remove surface dust at a pressure of 0.58 MPa. Subsequently, wipe and degrease the substrate surface with isopropanol and dry it at 23 °C for 35 minutes.

[0060] S2. Coat the primer with a coating amount of 155 g / m² and pre-dry it at 62 °C for 48 minutes to complete the substrate pretreatment.

[0061] S3. Spray the bottom layer slurry on the pretreated substrate. The bottom layer slurry consists of the following components: 48 parts of orthophthalic unsaturated polyester resin, 17 parts of biomass-modified phenolic prepolymer, 23 parts of modified hollow ceramic microspheres, 3.5 parts of nano-silica, and 1.5 parts of curing agent.

[0062] Among them, the preparation method of the biomass-modified phenolic prepolymer is as follows: Mix enzymatically hydrolyzed lignin and phenol at a mass ratio of 1:5, add a formaldehyde solution with a concentration of 37 wt%, and the molar ratio of phenol to formaldehyde is 1:1.8. Under the condition of pH = 9.4, control the reaction temperature at 84 °C and react for 2.2 hours. After cooling to 25 °C, adjust the pH to 6.7 with dilute hydrochloric acid and remove the moisture by vacuum rotary evaporation to obtain the biomass-modified phenolic prepolymer.

[0063] The preparation method of the modified hollow ceramic microspheres is as follows: Dry the hollow ceramic microspheres at 108 °C for 13 hours, put them into a 95% ethanol solution of KH-550 and stir for 2.3 hours. The dosage of KH-550 is 2.8% wt of the hollow ceramic microspheres. After filtration, dry at 82 °C for 4.5 hours to obtain the modified hollow ceramic microspheres.

[0064] The spraying process parameters of the bottom layer slurry are: spraying pressure 0.37 MPa, spraying distance 26 cm, and thickness 1.25 mm.

[0065] S4. Spray the pattern layer slurry and the transparent protective layer slurry on the bottom layer slurry in sequence, and then perform step-by-step curing on the sprayed plate. The curing temperature is first maintained at 63 °C for 1.3 hours, then at 83 °C for 2.2 hours, and finally at 122 °C for 0.7 hours. The cured plate is subjected to surface treatment, including sanding and polishing, to obtain a lightweight artificial granite plate.

[0066] Example 5

[0067] This example provides a preparation process for a lightweight artificial granite plate.

[0068] S1. Use a granite plate as the substrate, and use a high-pressure air gun to remove surface dust at a pressure of 0.52 MPa. Subsequently, wipe and degrease the substrate surface with isopropanol and dry it at 22 °C for 20 minutes.

[0069] S2. Apply the primer with a coating amount of 140 g / m² and pre-dry it at 55 °C for 40 minutes to complete the substrate pretreatment.

[0070] S3. Spray the bottom layer slurry on the pretreated substrate. The bottom layer slurry consists of the following components: 42 parts of o-phthalic unsaturated polyester resin, 16 parts of biomass-modified phenolic prepolymer, 24 parts of modified hollow ceramic microspheres, 2.5 parts of nano-silica, and 2.5 parts of curing agent.

[0071] Among them, the preparation method of the biomass-modified phenolic prepolymer is as follows: Mix enzymatic lignin and phenol in a mass ratio of 1:5, add a formaldehyde solution with a concentration of 37 wt%, the molar ratio of phenol to formaldehyde is 1:1.8, under the condition of pH = 9.6, control the reaction temperature at 86 °C, react for 2.8 hours, after cooling to 25 °C, adjust the pH to 6.6 with dilute hydrochloric acid, and remove water by vacuum rotary evaporation to obtain the biomass-modified phenolic prepolymer.

[0072] The preparation method of the modified hollow ceramic microspheres is as follows: Dry the hollow ceramic microspheres at 102 °C for 11 hours, put them into a 95% ethanol solution of KH-550 and stir for 2.0 hours. The dosage of KH-550 is 2.3% wt of the hollow ceramic microspheres. After filtration, dry at 75 °C for 3.5 hours to obtain the modified hollow ceramic microspheres.

[0073] The spraying process parameters of the bottom layer slurry are: spraying pressure 0.34 MPa, spraying distance 24 cm, and thickness 1.15 mm.

[0074] S4. Spray the pattern layer slurry and the transparent protective layer slurry on the bottom layer slurry in sequence, and then perform step-by-step curing on the sprayed plate. The curing temperature is first maintained at 58 °C for 1.4 hours, then at 78 °C for 2.3 hours, and finally at 118 °C for 0.6 hours. The cured plate is subjected to surface treatment, including sanding and polishing, to obtain the lightweight artificial granite plate.

[0075] Comparative Example 1

[0076] This comparative example provides a preparation process for lightweight artificial granite plates, which is different from Example 1 in that the biomass-modified phenolic prepolymer is not used in the bottom layer slurry.

[0077] S1. Use a granite plate as the substrate, use a high-pressure air gun to remove surface dust at a pressure of 0.5 MPa, and then wipe and degrease the substrate surface with isopropyl alcohol and dry it at 25 °C for 30 minutes.

[0078] S2. Apply the primer with a coating amount of 150 g / m² and pre-dry it at 60 °C for 45 minutes to complete the substrate pretreatment.

[0079] S3. Spray the bottom layer slurry on the pretreated substrate. The bottom layer slurry consists of the following components: 63 parts of o-phthalic unsaturated polyester resin, 22 parts of modified hollow ceramic microspheres, 3 parts of nano-silica, and 2 parts of curing agent.

[0080] The preparation method of the modified hollow ceramic microspheres is as follows: Dry the hollow ceramic microspheres at 105 °C for 12 hours, put them into a 95% ethanol solution of KH-550 and stir for 2 hours. The dosage of KH-550 is 2.5%wt of the hollow ceramic microspheres. After filtration, dry at 80 °C for 4 hours to obtain the modified hollow ceramic microspheres.

[0081] The spraying process parameters of the bottom layer slurry are: spraying pressure 0.35 MPa, spraying distance 25 cm, and thickness 1.2 mm.

[0082] S4. Spray the pattern layer slurry and the transparent protective layer slurry on the bottom layer slurry in sequence, and then cure the sprayed board step by step. The curing temperature is first maintained at 60 °C for 1 hour, then at 80 °C for 2 hours, and finally at 120 °C for 0.5 hour. The cured board is subjected to surface treatment, including sanding and polishing, to obtain the artificial granite board.

[0083] Comparative Example 2

[0084] This comparative example provides a preparation process of a lightweight artificial granite board, which is different from Example 2 in that unmodified ordinary hollow ceramic microspheres are used instead of modified hollow ceramic microspheres in the bottom layer slurry.

[0085] S1. Use a granite board as the substrate, and use a high-pressure air gun to remove surface dust at a pressure of 0.6 MPa. Subsequently, wipe and degrease the substrate surface with isopropanol and dry at 24 °C for 25 minutes.

[0086] S2. Coat the primer, and the primer coating amount is 145 g / m². Pre-dry at 58 °C for 42 minutes to complete the substrate pretreatment.

[0087] S3. Spray the bottom layer slurry on the pretreated substrate. The bottom layer slurry consists of the following components: 40 parts of o-phthalic unsaturated polyester resin, 15 parts of biomass-modified phenolic prepolymer, 25 parts of ordinary hollow ceramic microspheres, 4 parts of nano-silica, and 3 parts of curing agent.

[0088] The preparation method of the biomass-modified phenolic prepolymer is as follows: Mix enzymatically hydrolyzed lignin and phenol in a mass ratio of 1:5, add a formaldehyde solution with a concentration of 37wt%, and the molar ratio of phenol to formaldehyde is 1:1.8. Under the condition of pH = 9.3, control the reaction temperature at 83 °C and react for 2 hours. After cooling to 25 °C, adjust the pH to 7.0 with dilute hydrochloric acid and remove water by vacuum rotary evaporation to obtain the biomass-modified phenolic prepolymer.

[0089] The process parameters for spraying the bottom layer slurry are as follows: spraying pressure is 0.32 MPa, spraying distance is 23 cm, and thickness is 1.1 mm.

[0090] S4. Spray the pattern layer slurry and the transparent protective layer slurry on the bottom layer slurry in sequence, and then cure the sprayed board step by step. The curing temperature is first maintained at 55 °C for 1.5 hours, then at 75 °C for 2.5 hours, and finally at 115 °C for 0.8 hours. The cured board is subjected to surface treatment, including sanding and polishing, to obtain artificial granite board.

[0091] Performance testing

[0092] Select the artificial granite boards prepared in the examples and comparative examples as samples for performance testing.

[0093] 1. Density test: Conduct the test according to the standard of GB / T1463 - 2005. Cut the sample into test blocks with dimensions of 50 mm×50 mm×20 mm, measure their volume and mass, and calculate the density value.

[0094] 2. Compressive strength test: Conduct the test according to the standard of GB / T 1941 - 2009. Process the sample into a cube with dimensions of 100 mm×100 mm×100 mm, conduct the test on a universal material testing machine, with a loading rate of 1.0 mm / min, record the maximum compression load, and calculate the compressive strength.

[0095] 3. Flexural strength test: According to the standard of GB / T 17671 - 1999, prepare specimens with dimensions of 160 mm×40 mm×40 mm, use the three - point bending test method on a universal material testing machine, with a loading rate of 0.5 mm / min, measure the maximum flexural load of the specimen, and calculate the flexural strength.

[0096] 4. Abrasion resistance test: According to the standard of GB / T 9966.1 - 2001, use an abrasion tester to test the abrasion resistance of the sample, and measure the wear thickness after 1000 revolutions.

[0097] 5. Water absorption test: According to the standard of GB / T 23266 - 2009, dry the sample at 105 °C until it reaches a constant weight, measure the dry weight, then soak it in water for 48 hours, take it out, dry the surface and weigh it, and calculate the water absorption rate.

[0098] 6. Freeze - thaw resistance test: According to the standard of GB / T 2419 - 2005, soak the sample in water for 24 hours, then put it into an environment of - 20 °C and freeze it for 4 hours, and then put it into water at 20 °C to melt for 4 hours. Repeat 25 cycles, and test the strength loss rate of the sample.

[0099] Test data

[0100] Table 1. Test Results of Mechanical Properties

[0101]

[0102] Table 2. Test Results of Durability Performance

[0103]

[0104] Data Analysis

[0105] As can be seen from Table 1, the density range of Examples 1-5 is between 1945 and 2010 kg / m³. Compared with natural granite, a significant weight reduction effect is achieved. At the same time, the compressive strength of the examples is 63.5 - 68.2 MPa, and the flexural strength is 27.2 - 29.6 MPa. Although the compressive strength is lower than that of natural granite, the flexural strength is about 80% - 97% higher than that of natural granite, which is particularly important for the application of the board. In Comparative Example 1, the lack of biomass-modified phenolic prepolymer led to a decrease in the elastic modulus of the material, and in Comparative Example 2, the use of unmodified hollow ceramic microspheres caused poor interfacial bonding of the slurry.

[0106] As can be seen from Table 2, the mass change rate before and after water absorption of Examples 1-5 is only 0.15% - 0.17%, which is lower than that of natural granite and the comparative example samples, indicating that the material has good waterproof performance. In terms of water resistance, the mass change rate of the examples is 0.12% - 0.17%, which is significantly lower than that of the comparative examples, indicating that the material has excellent stability in a humid environment. The wear resistance test shows that the wear thickness of the examples is 0.025 - 0.030 mm, slightly higher than that of natural granite, but far superior to the comparative example samples. In the freeze-thaw resistance test, the strength loss rate of the examples is only 2.2% - 2.8%, close to that of natural granite, while the strength loss rates of the comparative example samples are as high as 5.6% and 7.8%, indicating that the material of the present invention has excellent freeze-thaw cycle resistance. The introduction of biomass-modified phenolic prepolymer significantly improves the toughness and environmental resistance of the material, while the use of modified hollow ceramic microspheres enhances the compatibility of the interface between the slurry and the microspheres, improving the overall performance of the composite material.

[0107] In summary, through the synergistic effect of substrate pretreatment, biomass-modified phenolic prepolymer and modified hollow ceramic microspheres, the present invention successfully prepares an artificial granite board with both light weight, high strength and excellent durability. Compared with natural granite, the density is reduced by more than 35%, and while the flexural strength is increased by more than 80%, it has durability performance not weaker than that of natural granite.

[0108] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. All equivalent changes and improvements made in accordance with the scope of the present invention application shall still fall within the scope covered by the patent of the present invention.

Claims

1. A preparation process of a lightweight artificial granite plate, characterized in that, It includes the following steps: S1. Pretreat the substrate; S2. Spray the bottom layer slurry on the pretreated substrate; S3. Spray the pattern layer slurry and the transparent protective layer slurry on the bottom layer slurry; S4. Cure the sprayed plate step by step, and perform surface treatment on the cured plate to obtain the lightweight artificial granite plate; Among them, the bottom layer slurry is composed of the following components: 40-50 parts of unsaturated polyester resin, 15-20 parts of biomass modified phenolic prepolymer, 20-25 parts of modified hollow ceramic microspheres, 2-4 parts of nano-silica, and 1-3 parts of curing agent; Among them, the preparation method of the modified hollow ceramic microspheres is: dry the hollow ceramic microspheres at 100-110°C for 10-14 hours, put them into a 95% ethanol solution of KH-550 and stir for 1.5-2.5 hours, filter and dry at 70-85°C for 3-5 hours to obtain the modified hollow ceramic microspheres; Among them, the preparation method of the biomass modified phenolic prepolymer is: mix enzymatically hydrolyzed lignin and phenol in a mass ratio of 1:5, add a formaldehyde solution with a concentration of 37wt%, under the condition of pH = 9.3-9.7, control the reaction temperature at 83-87°C, react for 2-3 hours, cool down to 25°C, and adjust the pH to 6.5-7.0 with dilute hydrochloric acid, and remove the moisture by vacuum rotary evaporation to obtain the biomass modified phenolic prepolymer; Among them, the pre-treatment of the substrate includes: selecting granite plates as the substrate, using a high-pressure air gun to remove surface dust, wiping and degreasing the surface with isopropyl alcohol, drying at room temperature for 20 to 40 minutes, coating a primer, and the primer coating amount is 140 to 160 g / m 2 , and pre-drying at a temperature of 55 to 65 °C for 40 to 50 minutes.

2. The preparation process of the lightweight artificial granite plate according to claim 1, characterized in that, The dosage of KH-550 is 2%-3%wt of the hollow ceramic microspheres.

3. The preparation process of the lightweight artificial granite plate according to claim 1, characterized in that, The molar ratio of phenol to formaldehyde is 1:1.

8.

4. The preparation process of the lightweight artificial granite slab according to claim 1, characterized in that, The spraying process parameters of step S2 are: spraying pressure is 0.32-0.38MPa, spraying distance is 23-27cm, and thickness is 1.1-1.3mm.

5. The preparation process of the light artificial granite plate according to claim 1, characterized in that, The unsaturated polyester resin is o-phthalic unsaturated polyester resin, and the molecular weight range is 2200-2800g / mol.

6. A lightweight artificial granite plate prepared by the preparation process according to any one of claims 1-5.

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