SiO2-ZrO2 / cork composite particle as well as preparation method and application thereof

Abstract

The invention relates to the technical field of cork materials, in particular to SiO2-ZrO2 / cork composite particles and a preparation method and application thereof. The SiO2-ZrO2 / cork composite particles are prepared by adopting a sol-gel method, enabling SiO2-ZrO2 sol to be in full contact with and permeate into each cork particle through a vacuum impregnation process, and then forming a firm SiO2-ZrO2 layer on the surface of the cork particle after aging and freeze drying. On one hand, the ratio of silicon to zirconium is accurately controlled, the enhancement effect is maximized on the premise of avoiding particle aggregation, and the indentation damage resistance and wear resistance of the composite material are synergistically improved, and on the other hand, by regulating and controlling the volume ratio of the water-ethanol mixed solvent, the hydrolytic stability and the coating uniformity of sol are effectively improved, and the composite material has good application prospects. The bonding strength of SiO2-ZrO2 on a cork base is enhanced, the applicability of SiO2-ZrO2 to floors and wallboards is enhanced, and a reliable technical path is provided for development of high-performance environment-friendly building materials.

Description

Technical Field

[0001] This invention relates to the field of cork materials technology, and in particular to a SiO2-ZrO2 / cork composite particle, its preparation method, and its application. Background Technology

[0002] Cork, as a natural and renewable resource, possesses excellent elasticity, sound insulation, and heat insulation properties due to its unique honeycomb structure, and is widely used in building decoration, sealing materials, and other fields. However, the mechanical strength defects of natural cork—especially its low hardness leading to easy indentation damage and high wear rate—severely restrict its application in load-bearing floors, high-traffic areas, and other scenarios.

[0003] Currently, the industry primarily enhances cork properties through physical impregnation or chemical cross-linking: for example, impregnation with phenolic resin increases hardness, but carries the risk of formaldehyde release; elastomer blending improves resilience, but sacrifices abrasion resistance. These methods often struggle to simultaneously improve environmental friendliness and mechanical properties. Furthermore, while traditional inorganic particle reinforcement strategies can increase hardness, their poor compatibility with the cork substrate interface easily leads to particle shedding or stress concentration, thus accelerating material failure.

[0004] To enhance the applicability of cork products in flooring and wall panels, there is an urgent need to develop a cork-based composite material that combines excellent mechanical properties and stability. Summary of the Invention

[0005] To address the shortcomings of existing methods, this invention provides SiO2-ZrO2 / cork composite particles, their preparation method, and applications. The SiO2-ZrO2 / cork composite particles are prepared using a sol-gel method. A high-pressure impregnation process ensures that the SiO2-ZrO2 sol fully contacts and penetrates each cork particle. After aging and freeze-drying, a robust SiO2-ZrO2 layer is formed on the surface of the cork particles.

[0006] The method for preparing SiO2-ZrO2 / cork composite particles includes the following steps:

[0007] (1) Cork is crushed and passed through a 20-40 mesh sieve. It is then ultrasonically cleaned with deionized water and anhydrous ethanol for 15 minutes each to remove dust and impurities. After filtration and drying, cork particles are obtained.

[0008] (2) Dissolve tetraethyl orthosilicate in a mixed solution of water and anhydrous ethanol, then add hydrochloric acid solution to pH 2-3, stir for 40-60 min, then add zirconium butoxide, heat to 85-95℃ and stir for 10-15 h to obtain SiO2-ZrO2 sol.

[0009] Preferably, the volume ratio of water to anhydrous ethanol is 1 to 4:1.

[0010] Preferably, the mass concentration of the hydrochloric acid solution is 35%.

[0011] Preferably, the molar ratio of tetraethyl orthosilicate to zirconium butoxide is 0.06:0.01~0.03.

[0012] (3) After mixing the cork particles and SiO2-ZrO2 sol, place them in a vacuum drying oven and let them stand for 60-90 min under a vacuum of 0.07-0.09 MPa to allow the SiO2-ZrO2 sol to penetrate into the pore structure of the cork particles. Then release the vacuum, take out the particles, and place them in a constant temperature oven at 40℃ for 12 h. Then take out the cork particles and soak them in water for 3 h, filter them, and then freeze dry them in a freeze dryer to obtain SiO2-ZrO2 / cork composite particles.

[0013] Preferably, the volume ratio of SiO2-ZrO2 sol to cork particles is 2:1.

[0014] Furthermore, the SiO2-ZrO2 / cork composite particles prepared by the above method will be applied in flooring and wall panels.

[0015] The beneficial effects of this invention are as follows:

[0016] This invention modifies cork particles with SiO2-ZrO2 sol and significantly improves the mechanical properties of cork-based composite materials by optimizing the solvent composition and silicon-zirconium element ratio in the sol-gel process. On one hand, optimizing the silicon-zirconium ratio maximizes their reinforcing effect while avoiding particle agglomeration, synergistically improving the composite material's resistance to indentation damage and abrasion resistance. On the other hand, controlling the volume ratio of the water-ethanol mixed solvent effectively improves the hydrolytic stability and coating uniformity of the sol, enhancing the bonding strength of SiO2-ZrO2 on the cork substrate and improving its applicability in flooring and wall panels. This provides a reliable technical path for the development of high-performance environmentally friendly building materials. Detailed Implementation

[0017] The present invention will be further described below with reference to embodiments and comparative examples.

[0018] Example 1:

[0019] (1) Cork (Hengsen Cork) was crushed through a 20-mesh sieve, placed in a beaker, and ultrasonically cleaned alternately with deionized water and anhydrous ethanol for 15 minutes each to remove dust and impurities. After filtration and drying, cork particles were obtained.

[0020] (2) Dissolve 0.06 mol tetraethyl orthosilicate in a mixed solution of 120 mL water and 30 mL anhydrous ethanol, then add hydrochloric acid solution (mass concentration of 35%) to adjust the pH to 3, stir for 60 min, then add 0.01 mol zirconium butoxide, heat to 95 °C and stir for 15 h to obtain SiO2-ZrO2 sol;

[0021] (3) After mixing the cork particles and SiO2-ZrO2 sol at a volume ratio of 2:1, the mixture was placed in a vacuum drying oven and allowed to stand for 60 min under a vacuum of 0.07 MPa. After filtration, the mixture was placed in a constant temperature oven at 40℃ for 12 h. Then, the cork particles were taken out and soaked in water for 3 h, filtered, and then placed in a freeze dryer for freeze drying for 48 h to obtain SiO2-ZrO2 / cork composite particles.

[0022] Example 2:

[0023] The difference between Example 2 and Example 1 is that the amount of zirconium n-butoxide added is 0.02 mol, otherwise it is the same as Example 1.

[0024] Example 3:

[0025] The difference between Example 3 and Example 1 is that the amount of zirconium n-butoxide added is 0.03 mol, and the rest is the same as in Example 1.

[0026] Example 4:

[0027] The difference between Example 4 and Example 1 is that the “mixed solution of 120 mL water and 30 mL anhydrous ethanol” in step (2) is changed to “mixed solution of 75 mL water and 75 mL anhydrous ethanol”, and the rest is the same as in Example 1.

[0028] Example 5:

[0029] The difference between Example 5 and Example 1 is that the "mixed solution of 120 mL water and 30 mL anhydrous ethanol" in step (2) is changed to "mixed solution of 100 mL water and 50 mL anhydrous ethanol", and the rest is the same as in Example 1.

[0030] Comparative Example 1:

[0031] The difference between Comparative Example 1 and Example 1 is that zirconium n-butoxide was not added; otherwise, they are the same as in Example 1.

[0032] Comparative Example 2:

[0033] The difference between Comparative Example 2 and Example 1 is that the amount of zirconium n-butoxide added is 0.04 mol, while the rest is the same as in Example 1.

[0034] Comparative Example 3:

[0035] The difference between Comparative Example 3 and Example 1 is that the "mixed solution of 120 mL water and 30 mL anhydrous ethanol" in step (2) is changed to "150 mL water", and the rest is the same as in Example 1.

[0036] The composite particles or cork particles (unmodified) obtained in the examples and comparative examples were mixed with polyurethane adhesive and acetone at a mass ratio of 10:1:3 and stirred evenly. The mixture was then placed in a mold for uniform spreading and hot-pressed at a temperature of 130 °C and a pressure of 6 MPa for 15 min to prepare cork boards with a thickness of 5 mm.

[0037] The ability of cork boards to resist indentation damage was tested according to ASTM F1914, and the test results are shown in Table 1.

[0038] Table 1

[0039] Indentation recovery rate (%, with a load of 1000N) Wear rate (%) Example 1 75.3 12.8 Example 2 85.6 8.5 Example 3 79.2 10.9 Example 4 77.8 11.2 Example 5 76.2 12.3 Comparative Example 1 62.1 17.5 Comparative Example 2 68.7 15.2 Comparative Example 3 60.5 18.8 Cork boards made from pure cork particles 58.5 22.3

[0040] Comparing the data in Table 1, under the condition of a fixed solvent system (water:ethanol = 4:1), when the amount of zirconium n-butoxide added increased from 0.01 mol (Example 1) to 0.02 mol (Example 2), the synergistic effect significantly enhanced the reinforcing effect of the composite particles, with the indentation recovery rate reaching a peak of 85.6% and the wear rate being the lowest at 8.5%. However, further increases in zirconium content to 0.03 mol (Example 3) and 0.04 mol (Comparative Example 2) led to a decrease in performance, presumably due to the agglomeration of sol particles caused by excessive zirconium or stress concentration within the composite material. The performance of the sample lacking zirconium (Comparative Example 1) was close to that of unmodified pure corkboard, confirming that the introduction of zirconium is the core factor endowing the material with excellent resistance to indentation damage and wear resistance. Under the condition of fixed zirconium butoxide addition (0.01 mol), compared with the baseline Example 1 (water:ethanol = 4:1), moderately increasing the ethanol ratio (Example 4:water:ethanol = 1:1; Example 5:water:ethanol = 2:1) can improve the sol properties, which is presumably due to its improvement in the coating uniformity and adhesion of SiO2-ZrO2 on the cork surface, thereby slightly improving the indentation recovery rate. Complete removal of ethanol (Comparative Example 3, water only) significantly degraded the performance.

[0041] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for preparing SiO2-ZrO2 / cork composite particles, characterized in that, Includes the following steps: (1) Cork is crushed, sieved, washed, and dried to obtain cork particles; (2) Dissolve tetraethyl orthosilicate in a mixed solution of water and anhydrous ethanol, then add hydrochloric acid solution to pH 2-3, stir for 40-60 min, then add zirconium butoxide, heat to 85-95℃ and stir for 10-15 h to obtain SiO2-ZrO2 sol. (3) After mixing the cork particles and SiO2-ZrO2 sol, place them in a vacuum drying oven and let them stand under vacuum conditions. Then release the vacuum, take out the particles, and place them in a constant temperature oven at 40℃ for 12 h. Then take out the cork particles and soak them in water for 3 h, filter them, and then freeze dry them in a freeze dryer to obtain SiO2-ZrO2 / cork composite particles.

2. The method for preparing SiO2-ZrO2 / cork composite particles as described in claim 1, characterized in that, In step (1), the cork is crushed and passed through a 20-40 mesh sieve.

3. The method for preparing SiO2-ZrO2 / cork composite particles as described in claim 1, characterized in that, In step (2), the volume ratio of water to anhydrous ethanol is 1 to 4:

1.

4. The method for preparing SiO2-ZrO2 / cork composite particles as described in claim 1, characterized in that, The molar ratio of tetraethyl orthosilicate to zirconium butoxide is 0.06:0.01~0.

03.

5. The method for preparing SiO2-ZrO2 / cork composite particles as described in claim 1, characterized in that, The step (2) is to stand under vacuum conditions for 60 to 90 minutes under vacuum conditions with a vacuum degree of 0.07 to 0.09 MPa.

6. The method for preparing SiO2-ZrO2 / cork composite particles as described in claim 1, characterized in that, In step (3), the volume ratio of SiO2-ZrO2 sol to cork particles is 2:

1.

7. A SiO2-ZrO2 / cork composite particle prepared by the method according to any one of claims 1-6.

8. The application of the SiO2-ZrO2 / cork composite particles as described in claim 7 in flooring and wall panels.