CN-121976175-A - High-conductivity composite microsphere and preparation method thereof

CN121976175ACN 121976175 ACN121976175 ACN 121976175ACN-121976175-A

Abstract

The invention provides a high-conductivity composite microsphere and a preparation method thereof, belonging to the technical field of conductive composite materials. When the nickel plating microsphere is subjected to chemical silver plating, two complexing agents with different functions are cooperatively introduced, wherein one complexing agent acts on ions dissolved out of a nickel layer, and the other complexing agent acts on silver ions to be deposited. Through the combined action of the two complexation reactions, the chemical environment of a deposition interface and the reduction deposition kinetics process of silver ions are cooperatively regulated, so that the silver ions are reduced and deposited on the surface of a cleaner nickel layer at a controlled rate, thereby directly forming a silver coating with fine particles and compact arrangement, improving the uniformity and compactness of the silver coating and the bonding firmness of the silver coating and the bottom nickel, and avoiding the use of toxic reducing agents in the preparation process.

Inventors

ZHU LINGJIE
Dai Yingang
You juan
TAO RENMEI
LIU YUAN
Li Xiaodie

Assignees

古泰(江苏)新材料有限公司

Dates

Publication Date: 20260505
Application Date: 20260126

Claims (10)

1. The preparation method of the high-conductivity composite microsphere is characterized by comprising the following steps of: S1, carrying out surface treatment on polymer microspheres to obtain activated microspheres; s2, placing the activated microspheres in a chemical nickel plating solution for reaction to obtain nickel plating microspheres; s3, sequentially performing alkali washing and acid washing on the nickel-plated microspheres to obtain pretreated nickel-plated microspheres; s4, placing the pretreated nickel-plated microspheres in a composite reaction solution containing a first complexing agent, and dropwise adding a silver-ammonia solution containing a second complexing agent for reaction to obtain composite microspheres; The first complexing agent is disodium ethylenediamine tetraacetate, and the second complexing agent is one or more selected from diethylenetriamine, triethylenetetramine, tetraethylenepentamine and ammonia water.
2. The method of producing highly conductive composite microspheres according to claim 1, wherein the surface treatment in step S1 comprises roughening treatment, sensitization treatment, and activation treatment performed in this order.
3. The method of preparing highly conductive composite microspheres according to claim 1, wherein the electroless nickel plating solution in step S2 comprises nickel sulfate, sodium citrate, sodium acetate, sodium hypophosphite and sodium hydroxide.
4. The method for preparing the high-conductivity composite microsphere according to claim 1, wherein in the step S3, the alkaline washing mixed solution used for alkaline washing comprises sodium hydroxide and dodecylphenol polyoxyethylene ether, and the acid washing mixed solution used for acid washing comprises sulfuric acid and dodecylphenol polyoxyethylene ether.
5. The method of preparing highly conductive composite microspheres according to claim 1, wherein in step S4, the composite reaction solution further comprises a reducing agent and a surfactant.
6. The method of producing highly conductive composite microspheres according to claim 1, wherein in step S4, the concentration of the first complexing agent in the composite reaction liquid is 5g/L to 20g/L.
7. The method of preparing highly conductive composite microspheres according to claim 1, wherein in step S4, the silver-ammonia solution is prepared by dissolving silver nitrate and a second complexing agent in water at a mass ratio of 1:1.8 to 1:2.2.
8. The method of claim 1, wherein in step S4, the second complexing agent is triethylenetetramine.
9. The method of producing highly conductive composite microspheres according to claim 1, wherein in step S1, the polymer microspheres are polystyrene microspheres.
10. A highly conductive composite microsphere prepared by the method of any one of claims 1 to 9.

Description

High-conductivity composite microsphere and preparation method thereof Technical Field The invention belongs to the technical field of conductive composite materials, and particularly relates to a high-conductivity composite microsphere and a preparation method thereof. Background The polymer microsphere is used as a substrate, a nickel layer and a silver layer are sequentially deposited on the surface of the polymer microsphere to construct a conductive structure, which is a preparation path known in the industry, and the nickel layer is expected to be utilized to improve the bonding state of the silver layer and the polymer substrate. In the actual operation carried out according to the preparation path, the phenomenon that the obtained silver coating shows the characteristics of wide particle size distribution and loose arrangement on the microscopic appearance after chemical silver plating is carried out on the surface of the nickel layer can be observed, and the volume resistivity value of the composite microsphere is increased after high-temperature and high-humidity environment test. In addition, part of the electroless plating process to achieve this path requires the use of formaldehyde as a reducing agent. Therefore, how to improve the microcosmic compactness and structural stability of the silver plating layer and reduce the dependence of the preparation process on specific harmful chemical agents under the framework of adopting the nickel layer as the intermediate layer is a problem to be solved in the field. Disclosure of Invention The invention overcomes the defects of the prior art and provides a high-conductivity composite microsphere and a preparation method thereof. In order to achieve the aim, the technical scheme adopted by the invention is that the preparation method of the high-conductivity composite microsphere comprises the following steps: S1, carrying out surface treatment on polymer microspheres to obtain activated microspheres; s2, placing the activated microspheres in a chemical nickel plating solution for reaction to obtain nickel plating microspheres; s3, sequentially performing alkali washing and acid washing on the nickel-plated microspheres to obtain pretreated nickel-plated microspheres; s4, placing the pretreated nickel-plated microspheres in a composite reaction solution containing a first complexing agent, and dropwise adding a silver-ammonia solution containing a second complexing agent for reaction to obtain composite microspheres; The first complexing agent is disodium ethylenediamine tetraacetate, and the second complexing agent is one or more selected from diethylenetriamine, triethylenetetramine, tetraethylenepentamine and ammonia water. Preferably, in step S1, the surface treatment includes roughening treatment, sensitization treatment, and activation treatment which are sequentially performed. Preferably, the electroless nickel plating solution in step S2 includes nickel sulfate, sodium citrate, sodium acetate, sodium hypophosphite and sodium hydroxide. Preferably, in the step S3, the alkaline washing mixed solution used for alkaline washing comprises sodium hydroxide and dodecylphenol polyoxyethylene ether, and the acid washing mixed solution used for acid washing comprises sulfuric acid and dodecylphenol polyoxyethylene ether. Preferably, in step S4, the composite reaction solution further includes a reducing agent and a surfactant. Preferably, in the step S4, the concentration of the first complexing agent in the composite reaction liquid is 5g/L to 20g/L. Preferably, in step S4, the silver ammonia solution is prepared by dissolving silver nitrate and the second complexing agent in water at a mass ratio of 1:1.8 to 1:2.2. Preferably, in step S4, the second complexing agent is triethylenetetramine. Preferably, in step S1, the polymer microspheres are polystyrene microspheres. The invention provides a further technical scheme that the high-conductivity composite microsphere is prepared by the preparation method. According to the invention, a reaction system containing two complexing agents with different functions is established in the chemical silver plating step, and the chemical environment of a deposition interface and a metal ion reduction process are regulated and controlled in a combined way, so that clear progress is made in the aspects of improving the quality of a plating layer and greening the process, the defects in the background technology are overcome, and the method has the following beneficial effects: In the first aspect, the first complexing agent disodium ethylenediamine tetraacetate is added into the composite reaction liquid in the silver plating step, and the disodium ethylenediamine tetraacetate can carry out a complexing reaction with nickel ions dissolved in a trace amount from the surface of the nickel-plated microsphere substrate to form a stable water-soluble complex. The action transfers the dissolved nickel ions from the solid-liq