A kind of micro-nano silver dispersion and preparation method thereof

Abstract

The invention discloses a micro-nano silver dispersion and a preparation method thereof, which belongs to the technical field of micro-nano powder dispersion, and solves the technical problem that the existing preparation method makes it easy for hard agglomeration to occur between silver powder particles. The method disclosed by the invention uses a coating agent to coat the surface of silver powder particles, and through a simple reaction, the silver powder particles can be dispersed in a solvent for a long time and stably to obtain a micro-nano silver dispersion. The whole process does not require drying, and there is no drying environment to volatilize the liquid carried on the surface of the silver powder, thereby causing the problem of hard agglomeration between the silver powder particles. The whole preparation process is simple and easy to operate, and has broad application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of micro-nano powder dispersion, and specifically relates to a micro-nano silver dispersion and a preparation method thereof. Background Art

[0002] When the powder reaches the micro-nano level, it will show some special properties, such as: quantum size effect, small size effect, surface effect, macro quantum tunneling effect, etc. These effects change the distribution of electrons and atoms on the surface of micro-nano particles, increase surface activity, and greatly expand its application field. Silver itself has excellent electrical, magnetic and optical properties. Micro-nano-level silver has a wide range of applications in photovoltaic power generation, electrical and electronic equipment, catalysts, medicine and health, etc. However, in general, the smaller the particle size of the silver powder, the larger the specific surface area, the greater the activity of the particles, and the greater the tendency of the particles to aggregate with each other, that is, the easier it is to agglomerate. The traditional silver powder preparation process usually includes a drying process, that is, the liquid carried on the surface of the silver powder is volatilized at an environment above 100°C. This process easily causes hard agglomerations between the silver powder particles, which in turn affects its application performance. Summary of the invention

[0003] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a micro-nano silver dispersion and a preparation method thereof, so as to solve the technical problem that the existing preparation method makes it easy for hard agglomeration to occur between silver powder particles.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] The invention discloses a method for preparing a micro-nano silver dispersion, comprising the following steps:

[0006] S1: mixing a silver nitrate solution and a dispersant solution to obtain a mixed solution; dropping a reducing agent solution into the mixed solution to react, and after the reaction is completed, obtaining a reaction solution; adding a coating agent solution to the reaction solution to react, removing the supernatant after the reaction, and obtaining a reaction product, silver powder;

[0007] S2: placing the reaction product silver powder into a dispersion solvent to obtain a micro-nano silver dispersion.

[0008] Further, the silver nitrate solution and the dispersant solution are mixed to obtain a mixed solution, and then the temperature of the mixed solution is adjusted to 25-50° C., and then the reducing agent solution is dropped into the mixed solution to react.

[0009] Furthermore, the reaction time is 15-30 minutes.

[0010] Furthermore, the mass concentrations of the silver nitrate solution, dispersant solution, reducing agent solution, and coating agent solution are 0.2-0.4 kg / L, 0.1-0.3 kg / L, 0.1-0.3 kg / L, and 0.1-0.2 kg / L, respectively.

[0011] Furthermore, the temperature of the reducing agent solution and the coating agent solution are both 25-50°C.

[0012] Furthermore, the dispersant solution is one or more of methyl cellulose solution, carboxymethyl cellulose solution, polyvinyl pyrrolidone solution, gum arabic solution, Tween 80 solution and CTAB solution.

[0013] Furthermore, the reducing agent solution is one or more of formaldehyde solution, ascorbic acid solution, hydrazine hydrate solution, hydrogen peroxide solution, sodium methane sulfonate solution and ammonium formate solution.

[0014] Furthermore, the coating agent solution is one or more of oleic acid solution, acrylic resin solution, tetraethyl orthosilicate solution, silane coupling agent KH560 solution and silane coupling agent KH570 solution.

[0015] Furthermore, before the reaction product silver powder is placed in the dispersion solvent, the reaction product silver powder is washed several times with a detergent; the detergent is one or more of deionized water, methanol, ethanol, and isopropanol; and the dispersion solvent is one of pineol, butyl carbitol, butyl carbitol acetate, and ethylene glycol.

[0016] Furthermore, in S1, the mass ratio of the silver nitrate solution, the dispersant solution, the reducing agent solution, and the coating agent solution is 1:(0.2-0.5):(0.2-0.8):(0.03-0.1).

[0017] Furthermore, the silver nitrate solution, dispersant solution, reducing agent solution, and coating agent solution are obtained by mixing a reaction solvent with silver nitrate, dispersant, reducing agent, and coating agent respectively; the reaction solvent is one of deionized water, methanol, ethanol, and isopropanol.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The invention discloses a method for preparing a micro-nano silver dispersion. The method comprises the following steps: coating the surface of silver powder particles with a coating agent, and achieving long-term and stable dispersion of the silver powder particles in a solvent through a simple reaction, so as to obtain the micro-nano silver dispersion. The whole process does not require drying, and there is no dry environment to volatilize the liquid carried on the surface of the silver powder, thereby causing the problem of hard agglomeration between the silver powder particles. The whole preparation process is simple and easy to operate, and the preparation process does not require a drying process, thus shortening the preparation process and being more energy-efficient. The silver powder particles dispersed in the solvent have good dispersibility and can be stably stored for a long time, and can be directly used to prepare silver slurry, and then used in different fields, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a physical picture of the micro-nano silver dispersion prepared in Example 1 of the present invention;

[0021] Figure 2 This is a scanning electron microscope image of silver particles in the micro-nano silver dispersion prepared in Example 1 of the present invention;

[0022] Figure 3 This is a physical picture of the micro-nano silver dispersion prepared in Example 2 of the present invention;

[0023] Figure 4 This is a scanning electron microscope image of silver particles in the micro-nano silver dispersion prepared in Example 2 of the present invention;

[0024] Figure 5 Schematic diagram of the silver powder surface being coated by a coating agent. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0026] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0027] Herein, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0028] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0029] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0030] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0031] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0032] Example 1

[0033] A method for preparing a micro-nano silver dispersion comprises the following steps:

[0034] Dissolve 1 kg of silver nitrate in 4 L of deionized water to obtain a silver nitrate solution, dissolve 0.2 kg of gum arabic in 1 L of deionized water to obtain a gum arabic solution, mix the silver nitrate solution and the gum arabic solution to obtain a mixed solution, and adjust the temperature of the mixed solution to 40° C. for standby use;

[0035] 0.6 kg of ascorbic acid was dissolved in 5 L of deionized water, and the temperature was adjusted to 40° C. to obtain an ascorbic acid solution. The ascorbic acid solution was added to the above mixed solution to react for 30 min. The temperature during the reaction was controlled at 40° C. After the reaction was completed, a reaction solution was obtained;

[0036] 0.06 kg of oleic acid was dissolved in 0.5 L of deionized water, and the temperature was adjusted to 40° C. to obtain an oleic acid solution. The oleic acid solution was added to the above reaction solution, and the reaction was continued under stirring for 30 minutes. The temperature during the reaction process (coating process) was controlled to be 40° C. The supernatant after the reaction was removed to obtain a reaction product silver powder; the reaction product silver powder was washed with deionized water and anhydrous ethanol for 3 times, respectively, and then the obtained silver powder was transferred to 0.12 kg of pine alcohol and stirred to obtain a gray micro-nano silver dispersion.

[0037] Example 2

[0038] A method for preparing a micro-nano silver dispersion comprises the following steps:

[0039] Dissolve 1 kg of silver nitrate in 4.5 L of deionized water to obtain a silver nitrate solution, dissolve 0.3 kg of polyvinyl pyrrolidone in 1.5 L of deionized water to obtain polyvinyl pyrrolidone, mix the silver nitrate solution and polyvinyl pyrrolidone to obtain a mixed solution, and adjust the temperature of the mixed solution to 25° C. for standby use;

[0040] Dissolve 0.5 kg of hydrogen peroxide in 5 L of deionized water, adjust the temperature to 25° C. to obtain a hydrogen peroxide solution, add the hydrogen peroxide to the above mixed solution to react for 20 minutes, and control the temperature during the reaction at 25° C. After the reaction is completed, a reaction solution is obtained;

[0041] 0.05 kg of tetraethyl orthosilicate was dissolved in 0.5 L of deionized water, and the temperature was adjusted to 25° C. to obtain a tetraethyl orthosilicate solution. The tetraethyl orthosilicate solution was added to the above reaction solution, and the reaction was continued under stirring for 20 minutes. The temperature during the reaction process (coating process) was controlled to be 25° C. The supernatant after the reaction was removed to obtain a reaction product silver powder; the reaction product silver powder was washed with deionized water and isopropanol for 3 times, respectively, and then the obtained silver powder was transferred to 0.1 kg of butyl carbitol and stirred to obtain a gray micro-nano silver dispersion.

[0042] Example 3

[0043] A method for preparing a micro-nano silver dispersion comprises the following steps:

[0044] Dissolve 1 kg of silver nitrate in 5 L of deionized water to obtain a silver nitrate solution, weigh 0.15 kg of methyl cellulose and 0.15 kg of carboxymethyl cellulose, dissolve them in 1 L of deionized water to obtain a dispersant solution, mix the silver nitrate solution and the dispersant solution to obtain a mixed solution, and adjust the temperature of the mixed solution to 50° C. for use;

[0045] Dissolve 0.6 kg of hydrazine hydrate in 3 L of deionized water, adjust the temperature to 50° C. to obtain a hydrazine hydrate solution, add the hydrazine hydrate solution to the above mixed solution to react for 15 minutes, and control the temperature during the reaction to be 50° C. After the reaction is completed, obtain a reaction solution;

[0046] Weigh 0.06 kg of acrylic resin, dissolve it in 0.6 L of deionized water, adjust the temperature to 50 ° C to obtain an acrylic resin solution, add the acrylic resin solution to the above reaction solution, continue to stir and react for 15 minutes, control the temperature of the reaction process (coating process) to 50 ° C, remove the supernatant after the reaction, and obtain a reaction product silver powder; wash the reaction product silver powder with methanol and anhydrous ethanol for 3 times, respectively, and then transfer the obtained silver powder to 0.12 kg of pine alcohol, and stir to obtain a gray micro-nano silver dispersion.

[0047] Example 4

[0048] A method for preparing a micro-nano silver dispersion comprises the following steps:

[0049] Dissolve 1 kg of silver nitrate in 2.5 L of deionized water to obtain a silver nitrate solution, weigh 0.1 kg of Tween 80 and dissolve it in 1 L of deionized water to obtain a dispersant solution, mix the silver nitrate solution and the dispersant solution to obtain a mixed solution, and adjust the temperature of the mixed solution to 45° C. for use;

[0050] 0.6 kg of formaldehyde was dissolved in 2 L of deionized water, and the temperature was adjusted to 45° C. to obtain a hydrazine hydrate solution. The hydrazine hydrate solution was added to the above mixed solution to react for 20 min. The temperature during the reaction was controlled at 50° C. After the reaction was completed, a reaction solution was obtained;

[0051] Weigh 0.05 kg of silane coupling agent KH560 and 0.05 kg of silane coupling agent KH570, dissolve them in 0.5 L of deionized water, adjust the temperature to 45 ° C, obtain a coating agent solution, add the coating agent solution to the above reaction solution, continue to stir and react for 20 minutes, control the temperature of the reaction process (coating process) to 45 ° C, remove the supernatant after the reaction, and obtain a reaction product silver powder; wash the obtained reaction product silver powder with deionized water and anhydrous ethanol for 3 times, respectively, and then transfer the obtained silver powder to 0.15 kg of ethylene glycol, and stir to obtain a gray micro-nano silver dispersion.

[0052] Example 5

[0053] A method for preparing a micro-nano silver dispersion comprises the following steps:

[0054] Dissolve 1 kg of silver nitrate in 5 L of deionized water to obtain a silver nitrate solution, weigh 0.15 kg of CTAB and dissolve it in 1 L of deionized water to obtain a dispersant solution, mix the silver nitrate solution and the dispersant solution to obtain a mixed solution, and adjust the temperature of the mixed solution to 35° C. for use;

[0055] 0.5 kg of sodium methanesulfonate was dissolved in 2 L of deionized water, and the temperature was adjusted to 35° C. to obtain a sodium methanesulfonate solution. The sodium methanesulfonate solution was added to the above mixed solution to react for 20 min. The temperature during the reaction was controlled at 35° C. After the reaction was completed, a reaction solution was obtained;

[0056] 0.06 kg of oleic acid was dissolved in 0.3 L of deionized water, and the temperature was adjusted to 35° C. to obtain a coating agent solution. The coating agent solution was added to the above reaction solution, and the reaction was continued under stirring for 20 minutes. The temperature during the reaction process (coating process) was controlled to be 35° C. The supernatant after the reaction was removed to obtain a reaction product silver powder; the reaction product silver powder was washed with anhydrous ethanol and isopropanol for 3 times, respectively, and then the obtained silver powder was transferred to 0.15 kg of butyl carbitol acetate and stirred to obtain a gray micro-nano silver dispersion.

[0057] Example 6

[0058] A method for preparing a micro-nano silver dispersion comprises the following steps:

[0059] 1 kg of silver nitrate was dissolved in 4 L of deionized water to obtain a silver nitrate solution, 0.15 kg of polyvinyl pyrrolidone was weighed and dissolved in 1 L of deionized water to obtain a dispersant solution, the silver nitrate solution and the dispersant solution were mixed to obtain a mixed solution, and the temperature of the mixed solution was adjusted to 40° C. for standby use;

[0060] 0.5 kg of ammonium formate was dissolved in 2 L of deionized water, and the temperature was adjusted to 40° C. to obtain an ammonium formate solution. The ammonium formate solution was added to the above mixed solution to react for 30 minutes. The temperature during the reaction was controlled at 40° C. After the reaction was completed, a reaction solution was obtained;

[0061] 0.06 kg of oleic acid was dissolved in 0.3 L of deionized water, and the temperature was adjusted to 40° C. to obtain a coating agent solution. The coating agent solution was added to the above reaction solution, and the reaction was continued under stirring for 30 minutes. The temperature during the reaction process (coating process) was controlled to be 40° C. The supernatant after the reaction was removed to obtain a reaction product silver powder; the reaction product silver powder was washed with deionized water and isopropanol for 3 times, respectively, and then the obtained silver powder was transferred to 0.12 kg of pine alcohol and stirred to obtain a gray micro-nano silver dispersion.

[0062] Example 7

[0063] A method for preparing a micro-nano silver dispersion comprises the following steps:

[0064] 1 kg of silver nitrate was dissolved in 3.5 L of deionized water to obtain a silver nitrate solution, 0.2 kg of polyvinyl pyrrolidone was weighed and dissolved in 1 L of deionized water to obtain a dispersant solution, the silver nitrate solution and the dispersant solution were mixed to obtain a mixed solution, and the temperature of the mixed solution was adjusted to 45° C. for standby use;

[0065] 0.5 kg of ascorbic acid was dissolved in 2 L of deionized water, and the temperature was adjusted to 45° C. to obtain an ascorbic acid solution. The ascorbic acid solution was added to the above mixed solution to react for 15 min. The temperature during the reaction was controlled at 45° C. After the reaction was completed, a reaction solution was obtained;

[0066] 0.03 kg of acrylic resin and 0.03 kg of ethyl orthosilicate were dissolved in 0.5 L of deionized water, and the temperature was adjusted to 45° C. to obtain a coating agent solution. The coating agent solution was added to the above reaction solution, and the reaction was continued under stirring for 20 minutes. The temperature during the reaction process (coating process) was controlled to be 45° C. The supernatant after the reaction was removed to obtain a reaction product silver powder; the reaction product silver powder was washed with deionized water and ethanol for 3 times, respectively, and then the obtained silver powder was transferred to 0.12 kg of butyl carbitol and stirred to obtain a gray micro-nano silver dispersion.

[0067] Figure 1 and Figure 3 The figures are the actual pictures of the micro-nano silver dispersions prepared in Example 1 and Example 2, respectively. From the figures, it can be seen that the prepared micro-nano silver dispersions are gray-black in color and can be stably stored without sedimentation.

[0068] Figure 2 and Figure 4 The figures are scanning electron microscope images of the silver particles in the micro-nano silver dispersions prepared in Example 1 and Example 2, respectively. From the figures, it can be seen that the silver particles in the micro-nano silver dispersions are well coated and have good dispersibility.

[0069] Figure 5 The figure shows a schematic diagram of a micro-nano silver dispersion. The surface of the silver powder is coated by a coating agent and can be well dispersed in a dispersion solvent.

[0070] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a micro-nano silver dispersion, characterized in that: The following steps are involved: S1: mixing a silver nitrate solution and a dispersant solution to obtain a mixed solution; dropping a reducing agent solution into the mixed solution to react, and after the reaction is completed, obtaining a reaction solution; adding a coating agent solution to the reaction solution to react, removing the supernatant after the reaction, and obtaining a reaction product, silver powder; S2: placing the reaction product silver powder into a dispersion solvent to obtain a micro-nano silver dispersion; In S1, the mass ratio of silver nitrate solution, dispersant solution, reducing agent solution and coating agent solution is 1: (0.2-0.5): (0.2-0.8): (0.03-0.1); Before placing the reaction product silver powder into the dispersion solvent, the reaction product silver powder is washed several times with a detergent; the detergent is one or more of deionized water, methanol, ethanol, and isopropanol; the dispersion solvent is one of pineol, butyl carbitol, butyl carbitol acetate, and ethylene glycol.

2. The method for preparing a micro-nano silver dispersion according to claim 1, characterized in that: The silver nitrate solution and the dispersant solution are mixed to obtain a mixed solution, and then the temperature of the mixed solution is adjusted to 25-50° C., and then the reducing agent solution is dropped into the mixed solution to react.

3. The method for preparing a micro-nano silver dispersion according to claim 1, characterized in that: The reaction time is 15-30min.

4. The method for preparing a micro-nano silver dispersion according to claim 1, characterized in that: The mass concentrations of the silver nitrate solution, dispersant solution, reducing agent solution and coating agent solution are 0.2-0.4 kg / L, 0.1-0.3 kg / L, 0.1-0.3 kg / L and 0.1-0.2 kg / L respectively.

5. The method for preparing a micro-nano silver dispersion according to claim 1, characterized in that: The temperature of the reducing agent solution and the coating agent solution are both 25-50°C.

6. The method for preparing a micro-nano silver dispersion according to claim 1, characterized in that: The dispersant solution is one or more of a methyl cellulose solution, a carboxymethyl cellulose solution, a polyvinyl pyrrolidone solution, an arabic gum solution, a Tween 80 solution and a CTAB solution.

7. The method for preparing a micro-nano silver dispersion according to claim 1, characterized in that: The reducing agent solution is one or more of formaldehyde solution, ascorbic acid solution, hydrazine hydrate solution, hydrogen peroxide solution, sodium methanesulfonate solution and ammonium formate solution.

8. The method for preparing a micro-nano silver dispersion according to claim 1, characterized in that: The coating agent solution is one or more of oleic acid solution, acrylic resin solution, tetraethyl orthosilicate solution, silane coupling agent KH560 solution and silane coupling agent KH570 solution.

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