Preparation Method and Application of Calcium Carbonate / Metal Carbon Skeleton Composite Conductive Filler

Abstract

The present invention provides a preparation method and application of a calcium carbonate / metal-organic framework composite conductive filler. The preparation of the conductive filler includes the following steps: S1. Using calcium sulfate as a raw material, adding a metal-organic framework material and water, and mixing them evenly to form a slurry; S2. Adding ammonia water to the slurry, and controlling the sulfur-nitrogen ratio to be 40-50%; S3. Passing carbon dioxide gas into the slurry of S2 for reaction, filtering and washing after the reaction is complete, and calcining the filter residue to obtain the calcium carbonate / metal-organic framework composite conductive filler. The preparation process of this filler is simple in operation, the obtained conductive filler has good stability, no other additives need to be added during the production process, and the cost is low and it is easy to promote.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite materials, and particularly relates to a preparation method and application of a calcium carbonate / metal carbon skeleton composite conductive filler. Background Art

[0002] Conductive coatings refer to functional coatings that are applied to non-conductive substrates to endow them with the ability to conduct current and dissipate static charges. Among all conductive coatings, antistatic coatings are the most widely used and have attracted increasing attention from scientific researchers and coating manufacturers. Antistatic coatings can be classified into structural (intrinsic) antistatic coatings and composite (additive) antistatic coatings according to different raw materials and preparation methods. The former uses conductive polymers as film-forming substances, and their antistatic effect mainly comes from the wetting conductive film formed on the polymer surface after adsorbing water molecules. However, currently, due to high costs and immature technologies, their use is restricted. Composite antistatic coatings use ordinary polymers as film-forming substances and uniformly incorporate conductive fillers to achieve antistatic effects by utilizing the conductive properties of the conductive fillers.

[0003] Currently, there are many types and preparation methods of composite antistatic coatings. According to the different conductive fillers added, they are mainly divided into metal-based, carbon-based, and metal oxide-based coatings, etc. Metal-based antistatic coatings have the best conductive performance, but due to the high price of metals, their production costs are relatively high. Carbon-based antistatic coatings are relatively low in price, but they have many disadvantages such as easy deposition and caking, poor dispersibility, difficult cleaning, and poor oil resistance. Metal oxide-based antistatic coatings are less practically used due to their poor conductive performance.

[0004] CN101923907A discloses a calcium carbonate / nickel composite conductive powder and its preparation method, which is prepared by an in-situ reduction method on the surface of calcium carbonate nano-assembled spheres. The process is complex, requiring the prior preparation of calcium carbonate nano-assembled spheres, and a coupling agent needs to be added during the composite process. The binding stability between metallic nickel and calcium carbonate nano-assembled spheres is relatively poor.

[0005] CN102982862A discloses the preparation of a nano-calcium carbonate-based light-colored conductive powder. Using CaCO3 as the core, positively charged chitosan and negatively charged PSS polyelectrolytes are successively assembled by a layer-by-layer assembly method to modify the surface of nano-calcium carbonate. Then, a mixed ethanol solution containing tin ions and indium ions is dropped into the surface-modified nano-calcium carbonate system, and finally, an antistatic coating is prepared. The antistatic coating prepared by this method has good stability and low resistivity, but the process is complex. Summary of the Invention

[0006] The present invention provides a preparation method and application of a calcium carbonate / metal carbon skeleton composite conductive filler, which can simplify the preparation process and improve the stability of the filler.

[0007] To achieve the above object, the present invention adopts the following technical solution: A preparation method of a calcium carbonate / metal carbon framework composite conductive filler, which is characterized by comprising the following steps:

[0008] S1. Using calcium sulfate as a raw material, adding a metal-organic framework material and water, and mixing evenly to form a slurry;

[0009] S2. Adding ammonia water to the slurry, and controlling the sulfur-nitrogen ratio to be 40-50%;

[0010] S3. Passing carbon dioxide gas into the slurry of S2 for reaction, filtering and washing after the reaction is complete, and calcining the filter residue to obtain the calcium carbonate / metal carbon framework composite conductive filler.

[0011] Further, the purity of the calcium sulfate is above 96%.

[0012] Further, the metal-organic framework material is Ni-MOF.

[0013] Further, the addition amount of the metal-organic framework material is 0.05-2% of the mass of the calcium sulfate.

[0014] Further, the reaction temperature in S2 is controlled at 70°C.

[0015] Further, the feeding amount of carbon dioxide in S3 is 50-500 mL / min.

[0016] Further, the calcination temperature in S3 is 600-700°C, and the time is 1-4 h.

[0017] The present invention also relates to the calcium carbonate / metal carbon framework composite conductive filler obtained by using the above preparation method.

[0018] The present invention also relates to the application of the calcium carbonate / metal carbon framework composite conductive filler in an antistatic coating.

[0019] In specific applications, in the antistatic coating, the addition amount of the conductive filler is 20-50% of the total mass of the coating.

[0020] The present invention has the following beneficial effects:

[0021] 1. The present invention uses calcium sulfate as a raw material, adds a metal-organic framework material during the process of preparing calcium carbonate from calcium sulfate, and through a one-step reaction, the metal-organic framework material is embedded inside and on the surface of the calcium carbonate structure. After calcination, the binding force between calcium carbonate and the metal-organic framework material is increased, and thus a calcium carbonate / metal-carbon framework composite conductive filler is obtained. The composite conductive material obtained after calcination has a good particle size distribution; its process operation is simple, the obtained conductive filler has good stability, no other additives need to be added during the production process, and the cost is low and it is easy to promote.

[0022] 2. After the composite of calcium carbonate and the metal-organic framework material is calcined, a calcium carbonate / metal-carbon framework composite conductive filler is obtained, which can provide conductivity through nickel-based and also increase conductivity through carbon-based.

[0023] 3. The present invention adds a metal-organic framework material during the process of preparing calcium carbonate from calcium sulfate. Compared with only preparing calcium carbonate from calcium sulfate, Ni-MOF can provide a micro-phase reaction space in the reaction, provide a reaction site for the conversion of the calcium sulfate metathesis reaction into nano-calcium carbonate, and the obtained calcium carbonate can be refined from the micron scale to the nano scale. Specific Embodiments

[0024] The following will describe the implementation schemes of the present invention in detail in conjunction with embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.

[0025] Example 1

[0026] Weigh 502 g of calcium sulfate (99 wt%) and mix it evenly with 0.5 g of Ni-MOF material (Ni-MIL-53), then add them to a reaction kettle, add water to adjust the solid-liquid ratio (mass ratio) to 8%, heat to 70 °C, introduce ammonia water with a mass concentration of 26%, control the sulfur-nitrogen ratio of the slurry to 40%, then introduce carbon dioxide gas with a flow rate of 300 mL / min. When the sulfate content in the reaction solution no longer increases, the reaction ends. After washing and filtering, the obtained filter residue is calcined at 650 °C for 2 h to obtain a calcium carbonate / nickel-based carbon framework composite conductive filler with a particle size of 88 nm.

[0027] Example 2

[0028] Weigh 502 g of calcium sulfate (98 wt%) and mix it evenly with 1 g of Ni-MOF material, then add them to a reaction kettle, add water to adjust the solid-liquid ratio to 10%, heat to 70 °C, introduce ammonia water to control the sulfur-nitrogen ratio of the slurry to 41%, then introduce carbon dioxide gas with a flow rate of 140 mL / min. When the sulfate content in the reaction solution no longer increases, the reaction ends. After washing and filtering, the obtained filter residue is calcined at 660 °C for 2 h 10 min to obtain a calcium carbonate / nickel-based carbon framework composite conductive filler with a particle size of 72 nm.

[0029] Example 3

[0030] Weigh 502 g of calcium sulfate (97 wt%) and mix it evenly with 2 g of Ni-MOF material, then add them into a reaction kettle. Add water to adjust the solid-liquid ratio to 15%, heat to 70 °C, introduce ammonia water to control the sulfur-nitrogen ratio of the slurry to 43%, and then introduce carbon dioxide gas with a flow rate of 140 mL / min. When the sulfate content in the reaction solution no longer increases, the reaction ends. Wash and filter, and calcine the obtained filter residue at 670 °C for 2 h 30 min to obtain a calcium carbonate / nickel-based carbon framework composite conductive filler with a particle size of 59 nm.

[0031] Example 4

[0032] Weigh 502 g of calcium sulfate (96 wt%) and mix it evenly with 3 g of Ni-MOF material, then add them into a reaction kettle. Add water to adjust the solid-liquid ratio to 10%, heat to 70 °C, introduce ammonia water to control the sulfur-nitrogen ratio of the slurry to 43%, and then introduce carbon dioxide gas with a flow rate of 100 mL / min. When the sulfate content in the reaction solution no longer increases, the reaction ends. Wash and filter, and calcine the obtained filter residue at 680 °C for 2 h 30 min to obtain a calcium carbonate / nickel-based carbon framework composite conductive filler with a particle size of 55 nm.

[0033] Example 5

[0034] Weigh 502 g of calcium sulfate (99 wt%) and mix it evenly with 4 g of Ni-MOF material, then add them into a reaction kettle. Add water to adjust the solid-liquid ratio to 15%, heat to 70 °C, introduce ammonia water to control the sulfur-nitrogen ratio of the slurry to 44%, and then introduce carbon dioxide gas with a flow rate of 250 mL / min. When the sulfate content in the reaction solution no longer increases, the reaction ends. Wash and filter, and calcine the obtained filter residue at 690 °C for 2 h 40 min to obtain a calcium carbonate / nickel-based carbon framework composite conductive filler with a particle size of 57 nm.

[0035] Example 6

[0036] Weigh 502 g of calcium sulfate (99 wt%) and mix it evenly with 5.02 g of Ni-MOF material, then add them into a reaction kettle. Add water to adjust the solid-liquid ratio to 15%, heat to 70 °C, introduce ammonia water to control the sulfur-nitrogen ratio of the slurry to 45%, and then introduce carbon dioxide gas with a flow rate of 100 mL / min. When the sulfate content in the reaction solution no longer increases, the reaction ends. Wash and filter, and calcine the obtained filter residue at 700 °C for 3 h to obtain a calcium carbonate / nickel-based carbon framework composite conductive filler with a particle size of 62 nm.

[0037] Example 7

[0038] Weigh 100 g of calcium sulfate (99 wt%) and mix it evenly with 1 g of Fe-MOF material, then add them into a reaction kettle. Add water to adjust the solid-liquid ratio to 20%, heat to 70 °C, introduce ammonia water to control the sulfur-nitrogen ratio of the slurry to 45%, and then introduce carbon dioxide gas with a flow rate of 100 mL / min. When the sulfate content in the reaction solution no longer increases, the reaction ends. Wash and filter, and calcine the obtained filter residue at 700 °C for 4 h to obtain a calcium carbonate / nickel-based carbon framework composite conductive filler with a particle size of 86 nm.

[0039] Example 8

[0040] Weigh 100 g of calcium sulfate (99 wt%) and mix it evenly with 1 g of Ni-MOF material, then add them into a reaction kettle. Add water to adjust the solid-liquid ratio to 15%, heat to 70 °C, introduce ammonia water to control the sulfur-nitrogen ratio of the slurry to 35%, and then introduce carbon dioxide gas with a flow rate of 100 mL / min. When the sulfate content in the reaction solution no longer increases, the reaction ends. Wash and filter, and calcine the obtained filter residue at 700 °C for 3 h to obtain a calcium carbonate / nickel-based carbon framework composite conductive filler with a particle size of 82 nm.

[0041] Example 9

[0042] Weigh 100 g of calcium sulfate (99 wt%) and mix it evenly with 1 g of Ni-MOF material, then add them into a reaction kettle. Add water to adjust the solid-liquid ratio to 15%, heat to 70 °C, introduce ammonia water to control the sulfur-nitrogen ratio of the slurry to 55%, and then introduce carbon dioxide gas with a flow rate of 100 mL / min. When the sulfate content in the reaction solution no longer increases, the reaction ends. Wash and filter, and calcine the obtained filter residue at 700 °C for 3 h to obtain a calcium carbonate / nickel-based carbon framework composite conductive filler with a particle size of 142 nm.

[0043] Example 10

[0044] Weigh 100 g of calcium sulfate (99 wt%) and mix it evenly with 1 g of Ni-MOF material, then add them into a reaction kettle. Add water to adjust the solid-liquid ratio to 15%, keep the temperature at 70 °C, introduce ammonia water to control the sulfur-nitrogen ratio of the slurry to 45%, and then introduce carbon dioxide gas with a flow rate of 100 mL / min. When the sulfate content in the reaction solution no longer increases, the reaction ends. Wash and filter, and calcine the obtained filter residue at 800 °C for 1 h to obtain a calcium carbonate / nickel-based carbon framework composite conductive filler with a particle size of 65 nm.

[0045] Example 11

[0046] Weigh 100 g of calcium sulfate (99 wt%) and mix it evenly with 3 g of Ni-MOF material, then add them to a reaction kettle. Add water to adjust the solid-liquid ratio to 15%, keep the temperature at 70 °C, introduce ammonia water to control the sulfur-nitrogen ratio of the slurry to 45%, and then introduce carbon dioxide gas with a flow rate of 100 mL / min. When the sulfate content in the reaction solution no longer increases, the reaction ends. Wash and filter, and calcine the obtained filter residue at 700 °C for 3 h to obtain a calcium carbonate / nickel-based carbon skeleton composite conductive filler with a particle size of 55 nm.

[0047] Example 12

[0048] Weigh 100 g of calcium sulfate (99 wt%) and mix it evenly with 1 g of Ni-MOF material, then add them to a reaction kettle. Add water to adjust the solid-liquid ratio to 15%, heat to 55 °C, introduce ammonia water to control the sulfur-nitrogen ratio of the slurry to 55%, and then introduce carbon dioxide gas with a flow rate of 100 mL / min. When the sulfate content in the reaction solution no longer increases, the reaction ends. Wash and filter, and calcine the obtained filter residue at 700 °C for 3 h to obtain a calcium carbonate / nickel-based carbon skeleton composite conductive filler with a particle size of 215 nm.

[0049] Example 13

[0050] Weigh 100 g of calcium sulfate (99 wt%) and mix it evenly with 1 g of Ni-MOF material, then add them to a reaction kettle. Add water to adjust the solid-liquid ratio to 15%, heat to 85 °C, introduce ammonia water to control the sulfur-nitrogen ratio of the slurry to 55%, and then introduce carbon dioxide gas with a flow rate of 100 mL / min. When the sulfate content in the reaction solution no longer increases, the reaction ends. Wash and filter, and calcine the obtained filter residue at 700 °C for 3 h to obtain a calcium carbonate / nickel-based carbon skeleton composite conductive filler with a particle size of 189 nm.

[0051] Comparative Example 1:

[0052] Weigh 100 g of calcium sulfate (99 wt%), add water to adjust the solid-liquid ratio to 15%, keep the temperature at 70 °C, introduce ammonia water to control the sulfur-nitrogen ratio of the slurry to 45%, and then introduce carbon dioxide gas with a flow rate of 100 mL / min. When the sulfate content in the reaction solution no longer increases, the reaction ends. Wash and filter, mix the obtained filter residue evenly with 1 g of Ni-MOF material, and then calcine it at 700 °C for 3 h to obtain a calcium carbonate / nickel-based carbon skeleton composite conductive filler with a particle size of 532 nm.

[0053] Comparative Example 2

[0054] Weigh 100 g of calcium sulfate (99 wt%) and mix it evenly with 1 g of Ni-MOF material, then add them into a reaction kettle. Add water to adjust the solid-liquid ratio to 15%, heat it to 50 °C, introduce ammonia water to control the sulfur-nitrogen ratio of the slurry to 45%, and then introduce carbon dioxide gas with a flow rate of 100 mL / min. When the sulfate content in the reaction solution no longer increases, the reaction ends. Wash and filter, and dry the filter residue at 100 - 120 °C to obtain a calcium carbonate / nickel-based carbon framework composite conductive filler with a particle size of 783 nm.

[0055] The above conductive fillers in the examples and comparative examples are used to prepare antistatic coatings, and their addition amount accounts for 35% of the total mass of the coatings. The obtained coatings are applied to the production of antistatic coatings. The testing method for the prepared coatings can be carried out using the methods and equipment known to those skilled in the art. Through performance testing, the test index data are shown in Table 1.

[0056] Resistivity (Ω) Hardness (H) Example 1 <![CDATA[10 6 > 3 Example 2 <![CDATA[10 6 > 3 Example 3 <![CDATA[10 5 > 3 Example 4 <![CDATA[10 4 > 4 Example 5 <![CDATA[10 3 > 4 Example 6 <![CDATA[10 2 > 5 Example 7 <![CDATA[10 10 > 4 Example 8 <![CDATA[10 8 > 4 Example 9 <![CDATA[10 10 > 2 Example 10 <![CDATA[10 3 > 3 Example 11 <![CDATA[10 3 > 3 Example 12 <![CDATA[10 4 > 3 Example 13 <![CDATA[10 3 > 3 Comparative Example 1 <![CDATA[10 4 > 1 Comparative Example 2 <![CDATA[10 8 > 2

[0057] It can be concluded that the hardness of Examples 1 - 6 is 1 - 2 grades higher than that of Comparative Example 1. This is because the Ni-MOF material can provide a microphase system during the reaction, which is beneficial to the preparation of nano-calcium carbonate, thus improving the material strength. Compared with Comparative Example 2, after calcination, the resistivity of Examples 1 - 6 decreases by several orders of magnitude due to the generation of carbon materials. Compared with Example 7, the resistivity of Examples 1 - 6 decreases by a large order of magnitude.

[0058] It should be noted that the above examples are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing examples, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A preparation method of a calcium carbonate / metal carbon framework composite conductive filler, characterized in that, It includes the following steps: S1. Using calcium sulfate as raw material, adding metal-organic framework material and water, and mixing evenly to form a slurry; S2. Adding ammonia water to the slurry, and controlling the sulfur-nitrogen ratio to be 40-50%; S3. Passing carbon dioxide gas into the slurry of S2 for reaction, filtering and washing after the reaction is complete, and calcining the filter residue to obtain the calcium carbonate / metal carbon framework composite conductive filler.

2. The preparation method according to claim 1, wherein: The purity of the calcium sulfate is above 96%.

3. The preparation method according to claim 1, characterized in that: The metal-organic framework material is a Ni-based MOF material.

4. The preparation method according to claim 1, characterized in that: The addition amount of the metal-organic framework material is 0.05-2% of the mass of calcium sulfate.

5. The preparation method according to claim 1, wherein: In S2, the temperature of the slurry is controlled at 60°C - 80°C.

6. The preparation method according to claim 1, characterized in that: In S3, the feeding amount of carbon dioxide is 50-500 mL / min.

7. The preparation method according to claim 1, characterized in that: In S3, the calcination temperature is 600-700°C, and the time is 1-4 h.

8. The calcium carbonate / metal carbon framework composite conductive filler obtained by the preparation method according to any one of claims 1-7.

9. The application of the calcium carbonate / metal carbon framework composite conductive filler according to claim 8 in antistatic coatings.

10. The application according to claim 9, wherein: In the antistatic coating, the addition amount of the conductive filler is 20-50% of the total mass of the coating.