CN111205593A

CN111205593A - Method for modifying filler surface by plasma

Info

Publication number: CN111205593A
Application number: CN201811389722.5A
Authority: CN
Inventors: 田付强; 夏宇
Original assignee: Suzhou Jufeng Insulation Material Co ltd; Suzhou Jufeng Advanced Materials Technology Co ltd
Current assignee: Suzhou Jufeng Insulation Material Co ltd; Suzhou Jufeng Advanced Materials Technology Co ltd
Priority date: 2018-11-21
Filing date: 2018-11-21
Publication date: 2020-05-29

Abstract

The invention discloses a method for modifying the surface of high-thermal-conductivity filler by using plasma. Firstly, the surface of the heat-conducting filler is treated by a low-temperature plasma treatment instrument in a water vapor atomization chamber, active groups are introduced to increase the concentration of surface hydroxyl, and then the surface treatment agent for the filler treated by the plasma is subjected to secondary coating treatment by a spray drying method. The filler treated by the method is filled into the high polymer insulating material, so that the effect of reducing the viscosity of the composite material can be realized.

Description

Method for modifying filler surface by plasma

Technical Field

The invention relates to filler surface treatment, in particular to a filler plasma surface modification treatment method for preparing a heat-conducting composite material by filling epoxy resin.

Background

With the development of large capacity, high power density and small and light weight of electrical equipment and the development of high speed and high density of micro-electronics and integrated circuits, the heat generated in unit volume of the equipment is increased rapidly, and the continuous accumulation of the heat can accelerate the aging failure of the insulating dielectric, thereby greatly reducing the reliability and the service life of the operation of the electrical and electronic equipment. The polymer insulating material is widely used for insulation of electrical equipment and encapsulation of microelectronic equipment due to the advantages of excellent dielectric property and the like. However, the thermal conductivity of the polymer insulating material is low. Therefore, in order to improve the heat dissipation capability of high power density electrical and electronic devices using polymer materials as insulating materials or packaging materials, it is necessary to modify the polymer materials to improve the thermal conductivity thereof. If the thermal conductivity of the polymer insulation composite material is to be improved significantly, the thermal conductivity of the polymer material cannot be solely depended on. Generally, the quality of the thermal conductivity depends on the thermal conductivity and the addition amount of the thermal conductive filler, and the thermal conductivity of the general composite material increases with the addition amount of the thermal conductive filler. However, when the heat conducting particles are added into the matrix of the high polymer material, the heat conducting particles are difficult to disperse in the matrix material due to the poor compatibility of the matrix and factors such as polarity, surface chemical groups and the like, and the viscosity is increased along with the dispersion of the heat conducting particles, so that the performance of the composite material is influenced, and certain difficulty is brought to practical application. Therefore, the surface modification treatment of the thermally conductive particles is required.

The surface modification treatment method of the filler particles includes a physical modification method, a chemical modification method and the like, and most of the researches adopt the chemical modification method at present. The research of domestic and foreign scholars finds that under the same conditions, the viscosity of the glue solution can be reduced to a certain extent by adding the filler treated by the surface treatment agent into the matrix. The chemical modification method requires the use of chemical reagents, inevitably causes environmental pollution, and in addition, when the amount of the surface treatment agent used is too small, modification treatment is insufficient, and when the amount of the surface treatment agent used is too large, thermal conductivity of the adhesive is reduced.

Disclosure of Invention

The invention aims to modify the surface of the filler by adopting a plasma modification method, improve the dispersibility of filler particles in a high-molecular matrix material and reduce the viscosity of a composite material.

Technical scheme

1. A method for modifying the surface of a filler is characterized in that: the filler is subjected to plasma surface modification treatment.

2. The filler types treated by the method comprise metal, electrodeless heat conducting particles and carbon materials.

3. The filler treated by the invention comprises the same filler compounded with different particle sizes and different fillers compounded.

4. The method comprises the following specific steps:

(1) firstly, putting a filler into an atomizing chamber for humidification treatment, wherein the treatment time is 1h, the pressure of an atomizing nozzle is 5MPa, and the flow rate is 0.1L/min;

(2) and placing the filler sample on a low-temperature plasma processor processing platform, and applying voltage to generate glow discharge. The discharge power is 5w-500w, the discharge voltage is 1kV-30kV, and the discharge time is 1min-10 h. After a predetermined time, the voltage was turned off and the sample was taken out. The discharge voltage, time, power and the like can be adjusted according to different fillers and process requirements.

5. The filler is subjected to plasma surface treatment and then is subjected to secondary treatment by using a surface treatment agent.

6. The surface treating agent used in the present invention includes coupling agent, organic monomer, organic oligomer, and surfactant, but is not limited to the above.

7. The surface treating agent of the invention carries out secondary treatment on the material by a spray drying method. The method comprises the following specific steps:

(1) mixing a surface treatment agent and filler particles to be treated in a stirrer to prepare slurry, wherein the ratio of the surface treatment agent to the filler to be treated is different according to the type of the treatment agent;

(2) the prepared slurry is sent into a centrifugal spray dryer by a peristaltic pump for spray drying treatment, the treatment temperature is 90-120 ℃, the treatment time is 10min-2h, the rotating speed of a spray drying agent atomizing disc is 750r/min-20000r/min, and the treatment time, the temperature and the rotating speed can be changed according to different requirements on the filler. The invention has the following beneficial effects:

the surface of the filler is treated by the plasma method, no chemical reagent is needed, and no pollution is caused. The treatment equipment can be recycled, and has economical efficiency. And the filler after the plasma surface treatment can play an obvious viscosity reducing effect when a high polymer material is filled to prepare the composite material.

Detailed Description

The surface treatment of Al2O3 particles was performed by a plasma surface treatment method, and the viscosity change of the filler-filled epoxy resin before and after the treatment was investigated.

Example 1

The raw materials and equipment used in the examples were:

flaky Al2O3

Silane coupling agent KH-560

Epoxy resin Epikote828

Mixer

Digital viscometer

Centrifugal spray drier

Peristaltic pump

Vacuum drying oven D29-6050

Low-temperature plasma treatment instrument

Electric heating constant temperature water bath

Planetary vacuum defoaming machine

Mixing and blending the flaky Al2O3 in a ratio of m (45um) to m (5um) to 3: 2 by a stirrer, drying in a vacuum drying oven, and then putting the Al2O3 filler on a processing platform of a low-temperature plasma processor, applying voltage to generate glow discharge with the discharge voltage of 3kV and the discharge power of 60W for 1 min. The voltage was then turned off and the sample was taken out. Immediately mixing the treated filler with a coupling agent KH-560, and preparing slurry by a stirrer, wherein the dosage of the coupling agent is 5% of the mass of the filler. And conveying the prepared slurry into a spray dryer by using a peristaltic pump for spray drying treatment, wherein the treatment temperature is 100 ℃, the treatment time is 30min, and the rotating speed of an atomizing disc is 1000 r/min. After the treatment, the mixture is added into epoxy resin Epikote828, the adding amount of the filler is 80wt percent, and then the mixture is placed into a planetary vacuum defoaming machine to be uniformly mixed. Heating the composite material and pure epoxy resin in a water bath to 90 ℃, recording the viscosity change of the composite material and the pure epoxy resin in the cooling process by using a digital viscometer (a 4# rotor is used in the experiment, the rotating speed is selected to be 60 r.m.p), and obtaining the viscosity test result shown in figure 1.

The above-described embodiments are intended to be illustrative only, and not to limit the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalent modifications thereto, which would occur to those skilled in the art upon reading the present disclosure.

FIG. 1 is a graph comparing the viscosity change of Al2O 3/epoxy composite (83 wt% loading) and neat epoxy treated with plasma surface modification in example 1 of the present invention.

Claims

1. A method for surface treatment of a filler, characterized by: the filler is subjected to plasma surface modification treatment.

2. The method of claim 1, wherein the filler comprises metal, inorganic heat-conducting particles and carbon material.

3. The filler surface modification treatment method according to claim 1, characterized in that the filler to be treated comprises the compounding of the same filler with different particle sizes and the compounding of different types of fillers.

4. The filler surface plasma treatment according to claim 1, characterized in that the method comprises the following specific steps:

5. The method of claim 4, wherein the filler is treated with a plasma surface and then treated with a surface treatment agent.

6. The surface treating agent according to claim 4, wherein the treating agent comprises a coupling agent, an organic monomer, an organic oligomer, a surfactant, but not limited thereto.

7. The secondary treatment according to claim 5, wherein the surface treatment agent is used for the secondary treatment of the material by a spray drying method.

8. A spray drying secondary process according to claim 7, characterised in that the process comprises the steps of:

(2) the prepared slurry is sent into a centrifugal spray dryer by a peristaltic pump for spray drying treatment, the treatment temperature is 90-120 ℃, the treatment time is 10min-2h, the rotating speed of a spray drying agent atomizing disc is 750r/min-20000r/min, and the treatment time, the temperature and the rotating speed can be changed according to different requirements on the filler.