Method for preparing silver-plated polystyrene composite microspheres and dispersion treatment equipment thereof

Abstract

According to the technical scheme, the method for preparing the silver-plated polystyrene composite microspheres comprises the following steps that S1, under the ultrasonic condition, 2-5 g of PS microspheres are added into 20-50 ml of concentrated sulfuric acid for roughening treatment, and the mass fraction of the concentrated sulfuric acid is 95%-98%; s2, under the ultrasonic condition, 2-5 g of PS microspheres obtained in the step S1 are added into 80-100 ml of a mixed solution of stannous chloride and concentrated hydrochloric acid for sensitization treatment, the mass fraction of stannous chloride is 4%-5%, the mass fraction of concentrated hydrochloric acid is 6%-8%, the mass fraction of concentrated hydrochloric acid is 36%-37%, and the ratio of stannous chloride to concentrated hydrochloric acid is 1: 2; the invention relates to dispersion treatment equipment for a method for preparing silver-plated polystyrene composite microspheres. According to the preparation method, the problems that the preparation cost of existing Ag-PS composite microspheres is high, and the silver shell layer is not pure and serious are solved, the preparation cost can be reduced, industrial production of the Ag-PS composite microspheres is achieved, meanwhile, the pure silver shell layer is generated, in addition, rapid mixing and rapid preparation can be carried out, and the production efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of preparing Ag-PS composite microspheres, and in particular to a method for preparing silver-plated polystyrene composite microspheres and a dispersion treatment device thereof. Background Art

[0002] The preparation of Ag-PS composite microspheres generally requires steps such as roughening, sensitization, activation pretreatment, and chemical silver plating. Concentrated sulfuric acid is generally used for roughening, a mixed solution of SnCl2 and HCl is generally used for sensitization, and a PbCl2 solution is generally used for activation. Among them, PbCl2 is expensive and easily forms large clusters of Sn and Pb, so it is generally not suitable for large-scale industrial production. At present, some studies have improved the process of preparing Ag-PS composite microspheres. For example, Ma Yuehui et al. prepared monodisperse Ag-coated PS composite microspheres with a diameter of 3μm through an improved chemical plating process. Catalytic centers are introduced through a series of pretreatments such as roughening, sensitization, and activation, and a denser Ag nanolayer is formed on the surface of the PS microspheres under the action of PVP. In addition, as the thickness of the silver shell increases from 35nm to 198nm, the volume conductivity of the composite microspheres increases from 1.16S / m to 3.57×10 4 S / m. This study used Pt sol to pre-activate PS microspheres, so that the PS surface was modified with Pt of about 10 nm in size, replacing the large clusters containing Sn and Pb obtained by the traditional activation method. However, the price of Pt sol is still relatively high. At the same time, both PbCl2 and Pt sol activation methods are prone to generate impurities in the generated silver shell layer. The presence of these impurities will have an adverse effect on the conductive properties of the composite microspheres. At the same time, most of the chemical plating processes mentioned in current studies use glucose as a reducing agent. When performing a chemical reduction reaction, glucose must be added to the tartaric acid solution and boiled to cause a reduction reaction, which greatly increases the difficulty of preparation. In addition, the Ag-PS composite microspheres prepared in the current study have serious agglomeration phenomena, and the existence of these agglomerations is not conducive to improving the conductive properties of the composite microspheres. In addition, PbCl2 is expensive and easily forms large clusters of Sn and Pb. The activation methods of PbCl2 and Pt sol are easy to generate impurities in the generated silver shell layer. The use of glucose as a reducing agent is complicated, and the Ag-PS composite microspheres have serious agglomeration phenomena. Therefore, we proposed a method for preparing silver-plated polystyrene composite microspheres and its dispersion processing equipment to solve the above problems. Summary of the invention

[0003] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a method for preparing silver-plated polystyrene composite microspheres and a dispersion treatment device thereof.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: A method for preparing silver-plated polystyrene composite microspheres comprises the following steps: S1. Under ultrasonic conditions, 2-5 g of PS microspheres are added to 20-50 ml of concentrated sulfuric acid for coarsening treatment, and the mass fraction of concentrated sulfuric acid is 95%-98%; S2. Under ultrasonic conditions, add 2-5 g of the PS microspheres obtained in step S1 to a mixed solution of 80-100 ml of stannous chloride and concentrated hydrochloric acid for sensitization treatment, wherein the mass fraction of stannous chloride is 4%-5%, the mass fraction of concentrated hydrochloric acid is 36%-37%, and the ratio of stannous chloride to concentrated hydrochloric acid is 1:2; S3, under ultrasonic conditions, add 2-5g of the PS microspheres obtained in step S2 into 100-120ml of silver ammonia solution for activation treatment, wherein the mass fraction of AgNO3 is 4%-5% and the concentration of silver nitrate is 0.3mol / L; S4. Silver plating: Under ultrasonic conditions, 5g of PS activated microspheres were added into silver ammonia solution with a silver nitrate concentration of 0.1mol / L, and 3% gum arabic was added. At 35°C, 10% formaldehyde solution was added dropwise for reduction. The reaction lasted for 1-2h to obtain PS / Ag composite microspheres.

[0005] Preferably, according to step S4, the mass fraction of AgNO3 in the silver ammonia solution is 2%-3%, the mass fraction of formaldehyde in the formaldehyde solution is 8%-10%, and the mass ratio of AgNO3 to PS microspheres is 3.5:1.

[0006] A dispersion processing device for preparing silver-plated polystyrene composite microspheres comprises a stirring box, a rotating device is installed on one side of the lower end of the stirring box, a stirring device is arranged in the stirring box, the rotating device and the stirring device are connected, a carrying box is connected on one side of the lower end of the stirring box, a protection box is installed on one side of the upper end of the stirring box, a shaking mechanism is arranged in the protection box, an auxiliary mixing mechanism is connected to the lower end of the shaking mechanism, the auxiliary mixing mechanism extends into the carrying box, a circulation mechanism is connected on one side of the carrying box, spray mechanisms are installed on both sides of the stirring box, and the circulation mechanism and the spray mechanism are connected, and an ultrasonic generating device is installed on one side of the stirring box.

[0007] Preferably, the stirring device comprises a stirring rod penetrating through one side of the stirring box, one end of the stirring rod is rotatably connected to one side of the stirring box, and a plurality of stirring blades are connected to a side wall of the stirring rod at equal intervals.

[0008] Preferably, the rotating device includes a mounting frame fixed to one side of the lower end of the mixing box, a second drive motor is installed on one side of the mounting frame, the output shaft of the second drive motor and one end of the mixing rod are fixedly sleeved with a transmission wheel, and a belt is sleeved between the two transmission wheels.

[0009] Preferably, the shaking mechanism includes two turntables rotatably connected between opposite side walls in the protection box, a rotating rod is commonly fixed between the two turntables, a second connecting rod is rotatably sleeved on the rotating rod, a first drive motor is fixed to one side of the protection box, and the output shaft of the first drive motor is connected to one end of one of the turntables.

[0010] Preferably, the auxiliary mixing mechanism includes a first connecting rod rotatably connected to the lower end of the second connecting rod, the lower end of the first connecting rod passes through the side wall of the mixing box and extends into the carrier box, and the lower end of the first connecting rod is fixedly mounted with the second tray and the first tray.

[0011] Preferably, the circulation mechanism comprises a first circulation pipe connected to one side of the carrier box, one end of the first circulation pipe is connected to a circulation pump, and one end of the circulation pump is connected to a second circulation pipe.

[0012] Preferably, the spray mechanism includes a fixed pipe connected to one end of the second circulation pipe, and delivery pipes are fixed on both sides of the fixed pipe. Multiple nozzles are obliquely provided on one side of the two delivery pipes, and the nozzles are cross-arranged with each other. Multiple through holes are evenly spaced on both sides of the mixing box, and the nozzles pass through the through holes and extend into the mixing box.

[0013] Preferably, a delivery pipe is connected to one side of the upper end of the mixing box, and a discharge pipe is connected to the lower end of the carrying box, and a valve is provided on the discharge pipe.

[0014] The present invention solves the current problems of high preparation cost of Ag-PS composite microspheres, impure silver shells and relatively serious problems. Silver ammonia solution is used to activate PS microspheres to replace PbCl2 and Pt sol in traditional activation methods, which can not only reduce the preparation cost to achieve industrial production of Ag-PS composite microspheres, but also generate relatively pure silver shells. At the same time, in order to simplify the operation of chemical silver plating, the present invention uses formaldehyde solution as a reducing agent to carry out the chemical silver plating process, and studies the influence of factors such as formaldehyde concentration, reaction temperature, AgNO3 concentration and the like on the coating during the silver plating process. In addition, in order to solve the agglomeration phenomenon of composite microspheres, the present invention studies the type and concentration of dispersants added in chemical plating, deeply explores the mechanism of different dispersants affecting the growth of silver shells, and determines the most suitable dispersant and its concentration for preparing Ag-PS composite microspheres.

[0015] The present invention has the following advantages: 1. The PS microspheres were activated with silver ammonia solution, which reduced the production cost and improved the purity of the silver layer, and increased the silver content in the composite microspheres to 71.9%; 2. Formaldehyde is used as a reducing agent to simplify the preparation process; 3. Adding gum arabic as a dispersant improves the agglomeration of composite microspheres; 4. The combination of ultrasonic equipment, circulation mechanism, spraying mechanism, stirring mechanism and auxiliary mixing mechanism greatly improves the preparation efficiency, while ensuring the stability and rapidity of the preparation; In summary, the present invention solves the current problems of high preparation cost and impure silver shell of Ag-PS composite microspheres, and can not only reduce the preparation cost to realize the industrial production of Ag-PS composite microspheres, but also generate a relatively pure silver shell layer, and can also perform rapid mixing and rapid preparation, thereby improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a diagram showing the internal structure of the mixing box of the present invention; Figure 2 This is an external structural diagram of the mixing box of the present invention; Figure 3 It is a structural diagram of the spray mechanism of the present invention; Figure 4 It is the structural diagram of the auxiliary mixing mechanism of the present invention; Figure 5 This is a structural diagram of the spray direction of the nozzle of the present invention; Figure 6 Thermogravimetric curves of original PS microspheres and activated PS microspheres; Figure 7 Thermogravimetric curves of PS microspheres and Ag / PS composite microspheres; Figure 8 A flow chart of the method for preparing silver-plated polystyrene composite microspheres according to the present invention; Fig. 9 is the SEM image of PS microspheres after activation; Fig.10 SEM and EDS images of Ag / PS composite microspheres.

[0017] In the figure: 1 protection box, 2 rotating rod, 3 turntable, 4 first driving motor, 5 delivery pipe, 6 stirring box, 7 stirring rod, 8 belt, 9 mounting frame, 10 second driving motor, 11 first tray, 12 second tray, 13 discharge pipe, 14 carrying box, 15 first circulation pipe, 16 circulation pump, 17 second circulation pipe, 18 stirring blade, 19 first connecting rod, 20 second connecting rod, 21 ultrasonic generating device, 22 through hole, 23 nozzle, 24 fixed pipe, 25 conveying pipe. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0019] Example 1 Reference Figure 6-10 , a method for preparing silver-plated polystyrene composite microspheres, comprising the following steps: S1. Under ultrasonic conditions, 5 g of PS microspheres were added to 50 ml of concentrated sulfuric acid for coarsening treatment, and the mass fraction of concentrated sulfuric acid was 98%; S2. Under ultrasonic conditions, 5 g of the PS microspheres obtained in step S1 were added to a mixed solution of 100 ml of stannous chloride and concentrated hydrochloric acid for sensitization treatment, wherein the mass fraction of stannous chloride is 4%, the mass fraction of concentrated hydrochloric acid is 8%, the mass fraction of concentrated hydrochloric acid is 36%-37%, and the ratio of stannous chloride to concentrated hydrochloric acid is 1:2; S3, under ultrasonic conditions, add 5g of the PS microspheres obtained in step S2 into 100ml of silver ammonia solution for activation treatment, wherein the mass fraction of AgNO3 is 5% and the concentration of silver nitrate is 0.3mol / L; S4. Silver plating: Under ultrasonic conditions, 5g of PS activated microspheres were added to silver ammonia solution with a silver nitrate concentration of 0.1mol / L, and 3% gum arabic was added. At 35°C, 10% formaldehyde solution was added dropwise for reduction. The reaction lasted for 1-2h to obtain PS / Ag composite microspheres, wherein the mass fraction of AgNO3 in the silver ammonia solution was 2%-3%, the mass fraction of formaldehyde in the formaldehyde solution was 8%-10%, and the mass ratio of AgNO3 to PS microspheres was 3.5:1.

[0020] The invention adopts silver ammonia solution to activate PS microspheres, reduces production cost and improves the purity of the silver layer, adopts formaldehyde as a reducing agent to simplify the preparation process, and adds gum arabic as a dispersant to reduce the agglomeration of composite microspheres.

[0021] Example 2 Reference Figure 1-10 , a method for preparing silver-plated polystyrene composite microspheres, comprising the following steps: S1. Under ultrasonic conditions, 5 g of PS microspheres were added to 50 ml of concentrated sulfuric acid for coarsening treatment, and the mass fraction of concentrated sulfuric acid was 98%; S2. Under ultrasonic conditions, 5 g of the PS microspheres obtained in step S1 were added to a mixed solution of 100 ml of stannous chloride and concentrated hydrochloric acid for sensitization treatment, wherein the mass fraction of stannous chloride is 4%, the mass fraction of concentrated hydrochloric acid is 8%, the mass fraction of concentrated hydrochloric acid is 36%-37%, and the ratio of stannous chloride to concentrated hydrochloric acid is 1:2; S3, under ultrasonic conditions, add 5g of the PS microspheres obtained in step S2 into 100ml of silver ammonia solution for activation treatment, wherein the mass fraction of AgNO3 is 5% and the concentration of silver nitrate is 0.3mol / L; S4. Silver plating: Under ultrasonic conditions, 5g of PS activated microspheres were added to silver ammonia solution with a silver nitrate concentration of 0.1mol / L, and 3% gum arabic was added. At 35°C, 10% formaldehyde solution was added dropwise for reduction. The reaction lasted for 1-2h to obtain PS / Ag composite microspheres, wherein the mass fraction of AgNO3 in the silver ammonia solution was 2%-3%, the mass fraction of formaldehyde in the formaldehyde solution was 8%-10%, and the mass ratio of AgNO3 to PS microspheres was 3.5:1.

[0022] The invention adopts silver ammonia solution to activate PS microspheres, reduces production cost and improves the purity of the silver layer, adopts formaldehyde as a reducing agent to simplify the preparation process, and adds gum arabic as a dispersant to reduce the agglomeration of composite microspheres.

[0023] A dispersion treatment device for preparing silver-plated polystyrene composite microspheres, comprising a stirring box 6, a rotating device is installed on one side of the lower end of the stirring box 6, the rotating device comprises a mounting frame 9 fixed to one side of the lower end of the stirring box 6, a second drive motor 10 is installed on one side of the mounting frame 9, the output shaft of the second drive motor 10 and one end of a stirring rod 7 are both fixedly sleeved with a transmission wheel, a belt 8 is sleeved between the two transmission wheels, and is used to drive the stirring device to rotate and stir; A stirring device is provided in the stirring box 6, and the rotating device is connected to the stirring device. The stirring device includes a stirring rod 7 which is arranged on one side of the stirring box 6, one end of the stirring rod 7 is rotatably connected to one side of the stirring box 6, and a plurality of stirring blades 18 are connected to the side wall of the stirring rod 7 at equal intervals. The second driving motor 10 drives the two transmission wheels to rotate by rotating the output shaft, and then drives the stirring rod 7 to rotate, and then performs mixing and stirring; A carrier box 14 is connected to one side of the lower end of the mixing box 6, and a protection box 1 is installed on one side of the upper end of the mixing box 6. A shaking mechanism is arranged in the protection box 1, and the shaking mechanism includes two turntables 3 rotatably connected between opposite side walls in the protection box 1, a rotating rod 2 is fixed between the two turntables 3, and a second connecting rod 20 is rotatably sleeved on the rotating rod 2. A first driving motor 4 is fixed to one side of the protection box 1, and the output shaft of the first driving motor 4 is connected to one end of one of the turntables 3, so as to drive the auxiliary mixing mechanism to shake up and down, so as to further improve the mixing effect; The lower end of the shaking mechanism is connected to an auxiliary mixing mechanism, which includes a first connecting rod 19 rotatably connected to the lower end of the second connecting rod 20, the lower end of the first connecting rod 19 penetrates the side wall of the mixing box 6 and extends into the carrier box 14, and the lower end of the first connecting rod 19 is fixedly sleeved with a second tray 12 and a first tray 11, and the first driving motor 4 drives the turntable 3 to rotate through the rotation of the output shaft, and then drives the rotating rod 2 to rotate, and as the rotating rod 2 rotates, the second connecting rod 20 is driven to rotate in circles, and as the second connecting rod 20 rotates in circles, the first connecting rod 19 is driven to swing up and down to achieve reciprocating movement, and the solution at the bottom is pulled up through the two trays at the lower end so that it can be fully contacted and mixed during stirring, thereby enhancing the contact surface and increasing the intensity of mixing; The auxiliary mixing mechanism extends into the carrier box 14. A circulation mechanism is connected to one side of the carrier box 14. The circulation mechanism includes a first circulation pipe 15 connected to one side of the carrier box 14. One end of the first circulation pipe 15 is connected to a circulation pump 16. One end of the circulation pump 16 is connected to a second circulation pipe 17. The internal solution is circulated through the circulation pump 16 to further improve the fusion effect. Spraying mechanisms are installed on both sides of the mixing box 6, and the circulation mechanism is connected to the spraying mechanism. An ultrasonic generating device 21 is installed on one side of the mixing box 6. The spraying mechanism includes a fixed pipe 24 connected to one end of the second circulation pipe 17. Delivery pipes 25 are fixed on both sides of the fixed pipe 24. A plurality of nozzles 23 are arranged obliquely on one side of the two delivery pipes 25, and the nozzles 23 are arranged crosswise with each other. A plurality of through holes 22 are evenly spaced on both sides of the mixing box 6. The nozzles 23 penetrate the through holes 22 and extend into the mixing box 6. The staggered nozzles 23 can improve the uniformity of spraying during spraying. Combined with the stirring of the auxiliary mixing mechanism and the stirring rod 7, the mixing efficiency is greatly improved and the mixing quality is guaranteed. The upper end of the mixing box 6 is connected to a delivery pipe 5, and the lower end of the carrying box 14 is connected to a discharge pipe 13. A valve is provided on the discharge pipe 13. After the mixing is completed, the valve is opened to discharge from the discharge pipe 13.

[0024] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing silver-plated polystyrene composite microspheres, characterized in that: The following steps are involved: S1. Under ultrasonic conditions, 2-5 g of PS microspheres are added to 20-50 ml of concentrated sulfuric acid for coarsening treatment, and the mass fraction of concentrated sulfuric acid is 95%-98%; S2. Under ultrasonic conditions, add 2-5 g of the PS microspheres obtained in step S1 to a mixed solution of 80-100 ml of stannous chloride and concentrated hydrochloric acid for sensitization treatment, wherein the mass fraction of stannous chloride is 4%-5%, the mass fraction of concentrated hydrochloric acid is 6%-8%, the mass fraction of concentrated hydrochloric acid is 36%-37%, and the ratio of stannous chloride to concentrated hydrochloric acid is 1:2; S3, under ultrasonic conditions, add 2-5g of the PS microspheres obtained in step S2 into 100-120ml of silver ammonia solution for activation treatment, wherein the mass fraction of AgNO3 is 4%-5% and the concentration of silver nitrate is 0.3mol / L; S4. Silver plating: Under ultrasonic conditions, 5g of PS activated microspheres were added into silver ammonia solution with a silver nitrate concentration of 0.1mol / L, and 3% gum arabic was added. At 35°C, 10% formaldehyde solution was added dropwise for reduction. The reaction lasted for 1-2h to obtain PS / Ag composite microspheres.

2. A method for preparing silver-plated polystyrene composite microspheres according to claim 1, characterized in that: According to step S4, the mass fraction of AgNO3 in the silver ammonia solution is 2%-3%, the mass fraction of formaldehyde in the formaldehyde solution is 8%-10%, and the mass ratio of AgNO3 to PS microspheres is 3.5:

1.

3. A dispersion treatment device for preparing silver-plated polystyrene composite microspheres, comprising a stirring box (6), characterized in that: A rotating device is installed on one side of the output end of the mixing box (6), a mixing device is provided in the mixing box (6), the rotating device and the mixing device are connected, a carrier box (14) is connected to one side of the lower end of the mixing box (6), a protection box (1) is installed on one side of the upper end of the mixing box (6), a shaking mechanism is provided in the protection box (1), the lower end of the shaking mechanism is connected to an auxiliary mixing mechanism, the auxiliary mixing mechanism extends into the carrier box (14), a circulation mechanism is connected to one side of the carrier box (14), spray mechanisms are installed on both sides of the mixing box (6), and the circulation mechanism and the spray mechanism are connected, and an ultrasonic generating device (21) is installed on one side of the mixing box (6).

4. The dispersion treatment equipment for preparing silver-plated polystyrene composite microspheres according to claim 3, characterized in that: The stirring device comprises a stirring rod (7) which is arranged to penetrate one side of a stirring box (6), one end of the stirring rod (7) is rotatably connected to one side of the stirring box (6), and a plurality of stirring blades (18) are connected to a side wall of the stirring rod (7) at equal intervals.

5. The dispersion treatment equipment for preparing silver-plated polystyrene composite microspheres according to claim 4, characterized in that: The rotating device comprises a mounting frame (9) fixed to one side of the lower end of the stirring box (6), a second drive motor (10) being mounted on one side of the mounting frame (9), a transmission wheel being fixedly mounted on an output shaft of the second drive motor (10) and one end of the stirring rod (7), and a belt (8) being mounted between the two transmission wheels.

6. The dispersion treatment equipment for preparing silver-plated polystyrene composite microspheres according to claim 3, characterized in that: The shaking mechanism comprises two rotating disks (3) rotatably connected between opposite side walls in the protection box (1); a rotating rod (2) is fixed between the two rotating disks (3); a second connecting rod (20) is rotatably sleeved on the rotating rod (2); a first driving motor (4) is fixed on one side of the protection box (1); an output shaft of the first driving motor (4) is connected to one end of one of the rotating disks (3).

7. The dispersion treatment equipment for preparing silver-plated polystyrene composite microspheres according to claim 6, characterized in that: The auxiliary mixing mechanism comprises a first connecting rod (19) rotatably connected to the lower end of a second connecting rod (20), the lower end of the first connecting rod (19) passing through a side wall of the mixing box (6) and extending into the carrier box (14), and the lower end of the first connecting rod (19) is fixedly sleeved with a second tray (12) and a first tray (11).

8. The dispersion treatment equipment for preparing silver-plated polystyrene composite microspheres according to claim 3, characterized in that: The circulation mechanism comprises a first circulation pipe (15) connected to one side of the carrier box (14), one end of the first circulation pipe (15) is connected to a circulation pump (16), and one end of the circulation pump (16) is connected to a second circulation pipe (17).

9. The dispersion treatment equipment for preparing silver-plated polystyrene composite microspheres according to claim 8, characterized in that: The spray mechanism comprises a fixed pipe (24) connected to one end of the second circulation pipe (17), delivery pipes (25) are fixed on both sides of the fixed pipe (24), a plurality of spray heads (23) are obliquely provided on one side of the two delivery pipes (25), and the spray heads (23) are arranged crosswise with each other, a plurality of through holes (22) are evenly spaced on both sides of the mixing box (6), and the spray heads (23) penetrate the through holes (22) and extend into the mixing box (6).

10. The dispersion treatment equipment for preparing silver-plated polystyrene composite microspheres according to claim 3, characterized in that: The upper end of the mixing box (6) is connected to a delivery pipe (5), and the lower end of the carrying box (14) is connected to a discharge pipe (13), and a valve is provided on the discharge pipe (13).

Images