A highly dispersible modified zinc oxide composite material and its preparation method

Abstract

This invention belongs to the field of zinc oxide synthesis technology, specifically relating to a highly dispersible modified zinc oxide composite material and its preparation method. The preparation method of this invention is as follows: CO2 is passed into a Ca(OH)2 aqueous solution to carry out a first carbonation reaction, obtaining a calcium carbonate slurry; the calcium carbonate slurry and a zinc ion solution are first mixed to obtain a mixture; the mixture is second mixed with carbonate ions, and the zinc ions and carbonate ions undergo an in-situ carbonation reaction on the surface of the calcium carbonate particles to obtain a zinc carbonate composite material; the zinc carbonate composite material is calcined to obtain a zinc oxide composite material; the zinc oxide composite material, a coupling agent, and water are third mixed to carry out a coupling reaction, obtaining a modified zinc oxide composite material. The preparation method of this invention can achieve in-situ growth of zinc carbonate on the surface of calcium carbonate, followed by calcination to decompose the zinc carbonate into zinc oxide, obtaining highly dispersible zinc oxide, which is then modified with a coupling agent to obtain highly dispersible modified zinc oxide.

Description

Technical Field

[0001] This invention belongs to the field of inorganic composite material synthesis technology, specifically relating to a highly dispersed modified zinc oxide composite material and its preparation method. Background Technology

[0002] Zinc oxide, commonly known as zinc white, is an essential additive in the rubber and tire industry. It can fully play its role in promoting vulcanization. Its high dispersibility can significantly improve the performance of rubber and reduce the mixing temperature, making it a future development direction for rubber additives.

[0003] Currently, the main method for preparing highly dispersible zinc oxide is the controlled precipitation method. The controlled precipitation method involves precipitating the zinc oxide precursor from the solution, followed by heat treatment and grinding to remove impurities, resulting in powdered zinc oxide. However, the powdered product consists of highly aggregated particles that clump together and are difficult to decompose, thus exhibiting poor dispersion performance. Summary of the Invention

[0004] In view of this, the present invention provides a highly dispersible modified zinc oxide composite material and a method for preparing the same. The modified zinc oxide composite material prepared by the method of the present invention exhibits high dispersibility.

[0005] To achieve the above objectives, the present invention provides a method for preparing highly dispersed zinc oxide, comprising the following steps:

[0006] A method for preparing a highly dispersible modified zinc oxide composite material includes the following steps:

[0007] CO2 is passed into an aqueous solution of Ca(OH)2 to carry out the first carbonation reaction, resulting in calcium carbonate slurry.

[0008] The calcium carbonate slurry and zinc ion solution are first mixed to obtain a mixture.

[0009] The mixture is mixed with carbonate ions in a second process, and zinc ions and carbonate ions undergo an in-situ carbonation reaction on the surface of calcium carbonate particles to obtain zinc carbonate composite material.

[0010] The zinc carbonate composite material includes calcium carbonate and zinc carbonate;

[0011] The zinc carbonate composite material is calcined to obtain a zinc oxide composite material.

[0012] The zinc oxide composite material includes calcium carbonate and zinc oxide;

[0013] The zinc oxide composite material, coupling agent, and water are mixed in a third process, and then a coupling reaction is carried out to obtain a modified zinc oxide composite material.

[0014] The calcination temperature is 350–600℃, and the time is 2–4 hours.

[0015] Preferably, the concentration of the Ca(OH)2 aqueous solution is 0.2 to 0.8 mol / L.

[0016] Preferably, the flow rate of CO2 into the Ca(OH)2 aqueous solution is 0.05 to 0.5 L / min.

[0017] Preferably, the zinc ion solution comprises one or more of zinc sulfate solution, zinc chloride solution, or zinc nitrate solution; the concentration of the zinc ion solution is 0.2–1.0 mol / L.

[0018] Preferably, the solid content of the calcium carbonate slurry is 1.5% to 2%; the volume ratio of the calcium carbonate slurry to the zinc source aqueous solution is 8 to 10:1.

[0019] Preferably, the molar ratio of zinc ions to carbonate ions is 1.0 to 1.5:1.

[0020] Preferably, the coupling agent includes one or more of silane coupling agents, titanate coupling agents, or aluminate coupling agents.

[0021] Preferably, the coupling agent is 0.5-10% of the mass of the zinc oxide composite material.

[0022] The present invention also provides a highly dispersible modified zinc oxide composite material prepared by the above-described technical solution, comprising calcium carbonate, zinc oxide anchored on the calcium carbonate, and a coupling agent grafted onto the surfaces of the calcium carbonate and zinc oxide; wherein the molar ratio of the calcium carbonate to the zinc oxide is 2.5 to 3.5:1.

[0023] Preferably, the calcium carbonate has a particle size of 50-100 nm, and the zinc oxide has a particle size of 2-5 nm.

[0024] This invention provides a method for preparing a modified zinc oxide composite material, comprising the following steps: passing CO2 into a Ca(OH)2 aqueous solution to perform a first carbonation reaction to obtain a calcium carbonate slurry; mixing the calcium carbonate slurry and a zinc source aqueous solution to obtain a mixture; mixing the mixture with a water-soluble carbonate and then performing a second carbonation reaction to obtain a zinc carbonate composite material; calcining the zinc carbonate composite material to obtain a zinc oxide composite material; and mixing the zinc oxide composite material, a coupling agent, and water in a third process and then performing a coupling reaction to obtain the modified zinc oxide composite material; the calcination temperature is 350–600°C, and the time is 2–4 hours. This invention first introduces CO2 into an aqueous solution of Ca(OH)2 for a primary carbonation reaction. By slowly introducing CO2 into the Ca(OH)2 solution, the reaction occurs simultaneously, resulting in a well-dispersible calcium carbonate slurry. Next, the calcium carbonate slurry is mixed with a zinc source aqueous solution. Due to the adsorption properties of calcium carbonate in the slurry, zinc ions are uniformly adsorbed onto the surface of the calcium carbonate. Then, water-soluble carbonates are added, causing zinc ions and calcium carbonate to grow in situ on the calcium carbonate surface, forming zinc carbonate. This allows the zinc carbonate to anchor onto the calcium carbonate surface, preventing agglomeration and achieving high dispersibility. Finally, the zinc carbonate composite is calcined at 350–600°C, converting the zinc carbonate anchored on the calcium carbonate surface into zinc oxide. Since the calcium carbonate does not decompose at this temperature, a zinc oxide composite with high dispersibility is obtained.

[0025] After obtaining the zinc oxide composite material, the present invention can further perform a coupling reaction between the zinc oxide composite material and a coupling agent. The zinc oxide composite material includes calcium carbonate and zinc oxide. The coupling reaction will cause the coupling agent to be grafted onto the surface of calcium carbonate and zinc oxide, thereby modifying the zinc oxide composite material and preparing a modified zinc oxide composite material with further improved dispersibility. Attached Figure Description

[0026] Figure 1 This is a low-magnification transmission electron microscope image of the modified zinc oxide composite material prepared in Example 1;

[0027] Figure 2 This is a high-magnification transmission electron microscope image of the modified zinc oxide composite material prepared in Example 1;

[0028] Figure 3 The image shows the contact angle of the modified zinc oxide composite material prepared in Example 1.

[0029] Figure 4 The contact angle test diagram of the modified zinc oxide composite material prepared in Example 2 is shown below.

[0030] Figure 5 The image shows the contact angle test results of the modified zinc oxide composite material prepared in Example 3.

[0031] Figure 6 The image shows the contact angle test results of the modified zinc oxide composite material prepared in Example 4.

[0032] Figure 7 The image shows the contact angle test results of the modified zinc oxide composite material prepared in Comparative Example 1. Detailed Implementation

[0033] This invention provides a method for preparing a highly dispersible modified zinc oxide composite material, comprising the following steps:

[0034] CO2 is passed into an aqueous solution of Ca(OH)2 to carry out the first carbonation reaction, resulting in calcium carbonate slurry.

[0035] The calcium carbonate slurry and zinc ion solution are first mixed to obtain a mixture.

[0036] The mixture is mixed with carbonate ions in a second process, and zinc ions and carbonate ions undergo an in-situ carbonation reaction on the surface of calcium carbonate particles to obtain zinc carbonate composite material.

[0037] The zinc carbonate composite material includes calcium carbonate and zinc carbonate;

[0038] The zinc carbonate composite material is calcined to obtain a zinc oxide composite material.

[0039] The zinc oxide composite material includes calcium carbonate and zinc oxide;

[0040] The zinc oxide composite material, coupling agent, and water are mixed in a third step, and then a coupling reaction is carried out to obtain a modified zinc oxide composite material.

[0041] Unless otherwise specified, all raw materials used in this invention are preferably commercially available products.

[0042] In this invention, CO2 is introduced into an aqueous solution of Ca(OH)2 to carry out a first carbonation reaction to obtain calcium carbonate slurry.

[0043] In this invention, the concentration of the Ca(OH)₂ aqueous solution is preferably 0.2–0.8 mol / L, more preferably 0.24–0.69 mol / L. In this invention, the flow rate of CO₂ introduced into the Ca(OH)₂ aqueous solution is preferably 0.05–0.5 L / min, more preferably 0.1–0.4 L / min.

[0044] In this invention, the first carbonization reaction is preferably carried out under stirring conditions, and the stirring speed is preferably 50-300 r / min. This invention does not specifically limit the time of the first carbonization reaction; the reaction is considered complete when the pH of the first carbonization reaction system is neutral, and the introduction of CO2 is stopped.

[0045] In this invention, the solid content of the calcium carbonate slurry is preferably 1.5% to 2%.

[0046] After obtaining the calcium carbonate slurry, the present invention performs a first mixing of the calcium carbonate slurry and zinc ion solution to obtain a mixture.

[0047] In this invention, the zinc ion solution preferably includes one or more of zinc sulfate solution, zinc chloride solution, and zinc nitrate solution, and is more preferably zinc sulfate. In this invention, the concentration of the zinc ion solution is preferably 0.2–1.0 mol / L, and more preferably 0.5–1.0 mol / L.

[0048] After obtaining the mixture, the present invention performs a second mixing with carbonate ions, and zinc ions and carbonate ions undergo an in-situ carbonation reaction on the surface of calcium carbonate particles to obtain zinc carbonate composite material.

[0049] In this invention, the carbonate ions are preferably provided by a water-soluble carbonate; the water-soluble carbonate preferably includes sodium carbonate and / or potassium carbonate. In this invention, the molar ratio of zinc ions to carbonate ions is preferably 1.0–1.5:1, more preferably 1.02–1.5.

[0050] In this invention, the temperature of the second carbonization reaction is preferably 40–60°C; the time of the second carbonization reaction is preferably 15–40 min, more preferably 20–40 min. In this invention, the second carbonization reaction is preferably carried out under stirring conditions, and the stirring speed is preferably 50–300 r / min.

[0051] In this invention, the zinc carbonate composite material includes calcium carbonate and zinc carbonate. In the second carbonation reaction stage, by setting the above parameters, in-situ growth of zinc carbonate on the surface of calcium carbonate can be achieved, so that zinc carbonate particles can be anchored on the surface of calcium carbonate, realizing the dispersion of zinc carbonate nanoparticles, and preparing for the subsequent calcination process.

[0052] After the second carbonization reaction, the present invention preferably further includes sequentially filtering, washing and drying the obtained second carbonization reaction system to obtain zinc carbonate composite material.

[0053] In this invention, the reagent used for filtration and washing is preferably deionized water or an aqueous ethanol solution, and the volume concentration of the aqueous ethanol solution is preferably ≥50%. In this invention, the drying temperature is preferably 160–180°C, and the drying time is preferably 60–90 min, more preferably 60–80 min.

[0054] After obtaining the zinc carbonate composite material, the present invention calcines the zinc carbonate composite material to obtain the zinc oxide composite material.

[0055] In this invention, the calcination temperature is 350–600°C, preferably 400–600°C; the rate of heating to the calcination temperature is preferably 3–5°C / min. The calcination time is preferably 2–4 hours, more preferably 2–3 hours. The calcination is preferably carried out under an argon protective atmosphere.

[0056] In this invention, the calcination temperature setting ensures that zinc carbonate decomposes into zinc oxide while preventing calcium carbonate from decomposing, thereby enabling zinc oxide to be anchored on the surface of calcium carbonate.

[0057] After obtaining the zinc oxide composite material, the present invention performs a third mixing of the zinc oxide composite material, coupling agent and water, and then carries out a coupling reaction to obtain the modified zinc oxide composite material.

[0058] In this invention, the coupling agent preferably includes one or more of silane coupling agents, titanate coupling agents, or aluminate coupling agents. In this invention, the mass of the coupling agent is preferably 0.5-10% of the mass of the zinc oxide composite material, more preferably 1-10%.

[0059] In this invention, the coupling reaction is preferably carried out under stirring conditions, the stirring speed is preferably 50-150 rpm, more preferably 80-100 rpm; the temperature of the coupling reaction is preferably 40-60℃, more preferably 50-60℃, and the time is preferably 20-40 min, more preferably 25-30 min.

[0060] After the coupling reaction is completed, the present invention further includes, preferably, filtering, washing and drying the obtained coupling reaction system in sequence to obtain a modified zinc oxide composite material.

[0061] In this invention, the operation and parameters of the filtration, washing and drying are not specifically limited, and can be set using operations and parameters well known to those skilled in the art.

[0062] The present invention also provides a highly dispersible modified zinc oxide composite material obtained by the preparation method described in the above technical solution.

[0063] In this invention, the highly dispersible modified zinc oxide composite material comprises calcium carbonate, zinc oxide anchored on the calcium carbonate, and a coupling agent grafted onto the surfaces of the calcium carbonate and zinc oxide.

[0064] In this invention, the particle size of the calcium carbonate is preferably 50-100 nm, the particle size of the zinc oxide is preferably 2-5 nm, and the molar ratio of the calcium carbonate to the zinc oxide is 2.5-3.5:1.

[0065] In this invention, the zinc oxide in the highly dispersible modified zinc oxide composite material is anchored on the surface of calcium carbonate, and a coupling agent is grafted onto the surfaces of the zinc oxide and the exposed calcium carbonate.

[0066] The following detailed description of the highly dispersible modified zinc oxide composite material and its preparation method provided by the present invention, with reference to specific embodiments, should not be construed as limiting the scope of protection of the present invention.

[0067] Example 1

[0068] CO2 was introduced into 204 mL of a 0.24 mol / L Ca(OH)2 aqueous solution at a flow rate of 0.2 L / min to carry out the first carbonation reaction. The first carbonation reaction was carried out under stirring at a speed of 50 r / min. When the pH of the first carbonation reaction system was neutral, the reaction was stopped to obtain calcium carbonate slurry with a solid content of 1.5%.

[0069] 230 mL of calcium carbonate slurry was first mixed with 23 mL of 0.52 mol / L zinc sulfate aqueous solution to obtain a mixture. The mixture was then second-mixed with 1.9 g of sodium carbonate, followed by a second carbonation reaction at 50 °C for 20 min under stirring at a speed of 50 r / min. After the second carbonation reaction, the resulting material was filtered and washed (using a 50% ethanol aqueous solution) and dried (at 170 °C for 60 min) to obtain a zinc carbonate composite material.

[0070] The zinc carbonate composite material was calcined at 550°C for 2 hours to obtain zinc oxide composite material.

[0071] The zinc oxide composite material, deionized water, and silane coupling agent (3% of the zinc oxide composite material by mass) were mixed and then subjected to a coupling reaction at 50°C for 30 min. The coupling reaction product was then filtered, washed, and dried to obtain the modified zinc oxide composite material.

[0072] The highly dispersed modified zinc oxide composite material obtained in Example 1 was examined by transmission electron microscopy (TEM). The TEM images are shown below. Figures 1-2 .from Figure 1 It can be seen that the calcium carbonate particles are well dispersed, with a particle size range of 50–100 nm. Figure 2 It can be seen that zinc oxide particles are anchored on the surface of calcium carbonate.

[0073] Example 2

[0074] CO2 was introduced into 204 mL of a 0.39 mol / L Ca(OH)2 aqueous solution at a flow rate of 0.1 L / min to carry out the first carbonation reaction. The first carbonation reaction was carried out under stirring at a speed of 200 r / min. When the pH of the first carbonation reaction system was neutral, the reaction was stopped to obtain calcium carbonate slurry with a solid content of 2.0%.

[0075] 175 mL of calcium carbonate slurry was mixed with 17.5 mL of 0.67 mol / L zinc sulfate aqueous solution to obtain a mixture. The mixture was then mixed with 1.7 g of sodium carbonate, followed by a second carbonation reaction at 40 °C for 25 min under stirring at 200 r / min. After the second carbonation reaction, the resulting system was filtered and washed (using a 50% ethanol aqueous solution) and dried (at 170 °C for 80 min) to obtain the zinc carbonate composite material.

[0076] The zinc carbonate composite was calcined at 400℃ (heating rate of 3℃ / min) for 2 hours to obtain zinc oxide composite.

[0077] The zinc oxide composite material, deionized water, and titanate coupling agent (1% of the zinc oxide composite material by mass) were mixed and then subjected to a coupling reaction at 50°C for 30 min. The coupling reaction product was then filtered, washed, and dried sequentially to obtain the modified zinc oxide composite material.

[0078] Example 3

[0079] CO2 was introduced into 204 mL of a 0.54 mol / L Ca(OH)2 aqueous solution at a flow rate of 0.3 L / min to carry out the first carbonation reaction. The first carbonation reaction was carried out under stirring at a speed of 300 r / min. When the pH of the first carbonation reaction system was neutral, the reaction was stopped to obtain a calcium carbonate slurry with a solid content of 2.5%.

[0080] 133.2 mL of the calcium carbonate slurry was mixed with 13.4 mL of a 0.82 mol / L zinc sulfate aqueous solution to obtain a mixture. The mixture was then mixed with 1.5 g of sodium carbonate, followed by a second carbonation reaction at 60 °C for 30 min under stirring at a speed of 300 r / min. After the second carbonation reaction, the resulting carbonation system was filtered and washed (using a 50% ethanol aqueous solution) and dried (at 160 °C for 60 min) to obtain a zinc carbonate composite material.

[0081] The zinc carbonate composite was calcined at 600℃ (heating rate of 3.5℃ / min) for 2 hours to obtain zinc oxide composite.

[0082] The zinc oxide composite material, deionized water, and aluminate coupling agent (10% of the zinc oxide composite material by mass) were mixed and then subjected to a coupling reaction at 50°C for 30 minutes. The coupling reaction product was then filtered, washed, and dried sequentially to obtain the modified zinc oxide composite material.

[0083] Example 4

[0084] CO2 was introduced into 204 mL of a 0.69 mol / L Ca(OH)2 aqueous solution at a flow rate of 0.4 L / min to carry out the first carbonation reaction. The first carbonation reaction was carried out under stirring at a speed of 100 r / min. When the pH of the first carbonation reaction system was neutral, the reaction was stopped to obtain calcium carbonate slurry with a solid content of 3.0%.

[0085] 102 mL of calcium carbonate slurry was mixed with 10.2 mL of 204 mL of 0.97 mol / L zinc sulfate aqueous solution to obtain a mixture. The mixture was then mixed with 1.3 g of sodium carbonate, followed by a second carbonation reaction at 55 °C for 40 min under stirring at 100 r / min. After the second carbonation reaction, the resulting system was filtered and washed (using a 50% ethanol aqueous solution) and dried (at 160 °C for 70 min) to obtain a zinc carbonate composite.

[0086] The zinc carbonate composite was calcined at 550℃ (heating rate of 4℃ / min) for 2 hours to obtain zinc oxide composite.

[0087] The zinc oxide composite material, deionized water, and silane coupling agent (3% of the zinc oxide composite material by mass) were mixed and then subjected to a coupling reaction at 50°C for 30 min. The coupling reaction product was then filtered, washed, and dried sequentially to obtain the modified zinc oxide composite material.

[0088] Comparative Example 1

[0089] The only difference from Example 1 is that calcium carbonate powder with a particle size of 1.5% is directly mixed and dispersed with water to obtain a calcium carbonate slurry with a solid content of 1.5%.

[0090] The remaining preparation steps are the same as in Example 1.

[0091] The modified zinc oxide composite materials obtained in Examples 1-4 and Comparative Example 1 were subjected to contact angle tests. The test results are shown in [Figure 1]. Figures 2-5 .

[0092] The test method is as follows: a water droplet is dropped onto the surface of a solid sample, and the shape of the droplet is obtained through a microscope and camera. The contact angle value is then measured using a HARKE-SPCA contact angle meter.

[0093] from Figures 2-5 It can be seen that the contact angle of Comparative Example 1 is 17.511°, the contact angle of the modified zinc oxide composite material prepared in Example 1 is 90.703°, the contact angle of the modified zinc oxide composite material prepared in Example 2 is 117.705°, the contact angle of the modified zinc oxide composite material prepared in Example 3 is 137.732°, and the contact angle of the modified zinc oxide composite material prepared in Example 4 is 100.863°. By comparison, the contact angle of the modified zinc oxide composite material provided by this invention is much larger than that of the comparative example, proving that the modified zinc oxide composite material provided by this invention has good dispersibility.

[0094] For those skilled in the art, various improvements and modifications can be made without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention.

Claims

1. A method for preparing a highly dispersible modified zinc oxide composite material, comprising the following steps: CO2 is passed into an aqueous solution of Ca(OH)2 to carry out the first carbonation reaction, resulting in calcium carbonate slurry. The calcium carbonate slurry and zinc ion solution are first mixed to obtain a mixture. The mixture is then mixed with carbonate ions in a second process, and zinc ions and carbonate ions undergo an in-situ carbonation reaction on the surface of calcium carbonate particles to obtain a zinc carbonate composite material; the zinc ion solution is one or more of zinc sulfate solution, zinc chloride solution, and zinc nitrate solution; the concentration of the zinc ion solution is 0.2~1.0 mol / L; The solid content of the calcium carbonate slurry is 1.5-2%; the volume ratio of the calcium carbonate slurry to the zinc ion solution is 8-10:

1. The zinc carbonate composite material comprises calcium carbonate and zinc carbonate; the zinc carbonate composite material is calcined to obtain a zinc oxide composite material; the zinc oxide composite material comprises calcium carbonate and zinc oxide. The zinc oxide composite material, coupling agent, and water are mixed in a third process, and then a coupling reaction is carried out to obtain a modified zinc oxide composite material; the calcination temperature is 350~600℃ and the time is 2~4h. The molar ratio of calcium carbonate to zinc oxide in the modified zinc oxide composite material is 2.5~3.5:1; The concentration of the Ca(OH)2 aqueous solution is 0.2~0.8 mol / L; The flow rate of CO2 into the Ca(OH)2 aqueous solution is 0.05~0.5 L / min.

2. The preparation method according to claim 1, characterized in that, The molar ratio of zinc ions to carbonate ions is 1.0~1.5:

1.

3. The preparation method according to claim 1, characterized in that, The coupling agent includes one or more of silane coupling agents, titanate coupling agents, or aluminate coupling agents.

4. The preparation method according to claim 1 or 3, characterized in that, The mass of the coupling agent is 0.5-10% of the mass of the zinc oxide composite material.

5. The highly dispersible modified zinc oxide composite material obtained by the preparation method according to any one of claims 1 to 4, characterized in that, It includes calcium carbonate, zinc oxide anchored on the calcium carbonate, and a coupling agent grafted onto the surfaces of the calcium carbonate and zinc oxide; the molar ratio of the calcium carbonate to zinc oxide is 2.5 to 3.5:

1.

6. The highly dispersible modified zinc oxide composite material according to claim 5, characterized in that, The calcium carbonate has a particle size of 50-100 nm, and the zinc oxide has a particle size of 2-5 nm.

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