阅读说明：本技术 一种等离子体处理氟化聚酰亚胺复合膜及其制备方法 (Plasma-treated fluorinated polyimide composite membrane and preparation method thereof ) 是由 鲍欣 李辉 于 2019-10-28 设计创作，主要内容包括：本发明提供一种等离子体处理氟化聚酰亚胺复合膜及其制备方法,将聚酰亚胺薄膜经等离子体处理得到表面具有大量含氟基团的氟化聚酰亚胺薄膜,再均匀的刷涂聚全氟乙丙烯或聚四氟乙烯乳液,经高温处理后得到复合膜。利用含氟气体进行等离子体处理聚酰亚胺薄膜的方法成本低、耗时短、无废弃物,制备的复合膜具有良好的绝缘、抗静电、耐高低温、耐腐蚀等特性。(The invention provides a plasma-treated fluorinated polyimide composite membrane and a preparation method thereof. The method for treating the polyimide film by using the fluorine-containing gas to carry out plasma has the advantages of low cost, short time consumption and no waste, and the prepared composite film has the characteristics of good insulation, antistatic property, high and low temperature resistance, corrosion resistance and the like.)

1. The plasma treated fluorinated polyimide composite film is characterized by being formed by compounding a plasma treated polyimide film and fluorine-containing emulsion.

2. The method of claim 1, wherein the fluorinated polyimide composite film is prepared by uniformly brush-coating a fluorine-containing emulsion on the plasma-treated polyimide film and drying the plasma-treated polyimide film by multi-stage heating.

3. The method according to claim 2, wherein the fluorine-containing emulsion is one or both of a perfluoroethylene-propylene emulsion and a polytetrafluoroethylene emulsion, and the emulsion has a particle size of 0.10 to 0.80 μm and a solid content of 10 to 50% (mass fraction).

4. The preparation method according to claim 2, wherein the multi-stage heating is performed by heating from room temperature to 90-110 ℃ and keeping the temperature for 5-30 min; heating to 210-230 ℃, keeping the temperature for 1-20 min, heating to 280-300 ℃, keeping the temperature for 1-20 min, cooling to 210-230 ℃, keeping the temperature for 1-20 min, cooling to 90-110 ℃, keeping the temperature for 5-30 min, cooling to 50-70 ℃, keeping the temperature for 5-30 min, wherein the heating rate of the first stage is 1-20 ℃/min, the heating rate of the second stage is 5-30 ℃/min, the heating rate of the third stage is 1-20 ℃/min, the cooling rate of the fourth stage is 5-30 ℃/min, the cooling rate of the fifth stage is 5-30 ℃/min, and the cooling rate of the sixth stage is 1-20 ℃/min.

5. The method of claim 2, wherein the plasma-treated polyimide film is prepared by: and (2) putting the polyimide film into absolute ethyl alcohol to be soaked for 5-60 min, taking out the polyimide film, airing the polyimide film on the surface of the filter paper, putting the pretreated polyimide film into a plasma reactor with set voltage, and carrying out plasma surface treatment under different fluorine-containing gases and certain working pressure to obtain the polyimide film with the fluorine-containing groups on the surface.

6. The method according to claim 2, wherein a contact angle of the polyimide film having a fluorine-containing group on the surface thereof is greater than 130 °.

7. The method according to claim 5, wherein the set voltage is 500 to 600V, the fluorine-containing gas is one or a mixture of two of fluorine gas, hydrogen fluoride and hexafluoropropylene oxide, the working pressure is 10 ~ 1000Pa, and the treatment time is 1min ~ 60 min.

8. The plasma-treated fluorinated polyimide composite film according to claim 1, wherein the tensile strength of the plasma-treated fluorinated polyimide composite film is 50-200 MPa, the elongation at break is 10-180%, the elastic modulus is 700-3500 MPa, the water contact angle is greater than 100 degrees, the dielectric constant is less than 7, the dielectric loss is less than 0.007, the withstand temperature is 180-300 ℃, and the thermal shrinkage rate is less than 1%.

9. The plasma-treated fluorinated polyimide composite film according to claim 1 can be used as a separator of an electric heating sheet.

Technical Field

The invention relates to a plasma-treated fluorinated polyimide composite membrane and a preparation method thereof, belonging to the field of preparation of composite membrane materials.

Background

The polyimide film has excellent high and low temperature resistance, insulation, corrosion resistance and other performances, and is widely applied to slot insulation of motors, cable wrapping materials and the like. However, the pure polyimide film has smooth surface, lower chemical surface energy and relatively poorer bonding performance with other materials, and the bonding performance between the surface of the pure polyimide film and the material to be coated can be improved by modifying the surface of the pure polyimide film. At present, the commonly used industrialized polyimide composite membrane is mainly characterized in that polyperfluorinated ethylene propylene is introduced into polyimide to improve the mechanical property and the insulating property of the polyimide and widen the application range of the polyimide. The polyimide film is subjected to plasma surface modification treatment by adopting fluorine-containing gas, so that a fluorine-containing group is grafted on the surface, the interaction force with fluorine-containing materials such as fluorinated ethylene propylene and polytetrafluoroethylene is improved, the bonding performance with the materials is improved, and a new direction is provided for the research and application of polyimide film materials.

Disclosure of Invention

In order to solve the above problems, the present invention provides a plasma-treated fluorinated polyimide composite membrane and a method for preparing the same.

The invention is realized by the following technical scheme.

The plasma treated fluorinated polyimide composite film is characterized by being formed by compounding a plasma treated polyimide film and fluorine-containing emulsion.

A preparation method of a plasma-treated fluorinated polyimide composite membrane is characterized in that fluorine-containing emulsion is uniformly brushed on a polyimide film subjected to plasma treatment, and the polyimide film is dried in a multi-stage heating mode to obtain the composite membrane.

The fluorine-containing emulsion is one or two of fluorinated ethylene propylene emulsion and polytetrafluoroethylene emulsion, the particle size of the emulsion is 0.10-0.80 mu m, and the solid content is 10-50% (mass fraction)

The multi-stage heating mode is characterized in that the temperature is increased from room temperature to 90-110 ℃, and the temperature is kept for 5-30 min; heating to 210-230 ℃, keeping the temperature for 1-20 min, heating to 280-300 ℃, keeping the temperature for 1-20 min, cooling to 210-230 ℃, keeping the temperature for 1-20 min, cooling to 90-110 ℃, keeping the temperature for 5-30 min, cooling to 50-70 ℃, keeping the temperature for 5-30 min, wherein the heating rate of the first stage is 1-20 ℃/min, the heating rate of the second stage is 5-30 ℃/min, the heating rate of the third stage is 1-20 ℃/min, the cooling rate of the fourth stage is 5-30 ℃/min, the cooling rate of the fifth stage is 5-30 ℃/min, and the cooling rate of the sixth stage is 1-20 ℃/min.

The preparation method of the plasma treated polyimide film comprises the following steps: and (2) putting the polyimide film into absolute ethyl alcohol to be soaked for 5-60 min, taking out the polyimide film, airing the polyimide film on the surface of the filter paper, putting the pretreated polyimide film into a plasma reactor with set voltage, and carrying out plasma surface treatment under different fluorine-containing gases and certain working pressure to obtain the polyimide film with the fluorine-containing groups on the surface.

The contact angle of the polyimide film with the fluorine-containing group is more than 130 degrees.

The set voltage is 500-600V, the fluorine-containing gas is one or a mixture of two of fluorine gas, hydrogen fluoride and hexafluoropropylene oxide, the working pressure is 10 ~ 1000Pa, and the treatment time is 1min ~ 60 min.

The polyimide film is prepared from polyimide acid through a tape casting method and imidization, and the thickness of the polyimide film is 5-300 mu m.

The high-temperature-resistant plasma-treated fluorinated polyimide composite film prepared by the preparation method has the advantages of tensile strength of 50-200 MPa, elongation at break of 10-180%, elastic modulus of 700-3500 MPa, water contact angle of more than 100 degrees, dielectric constant of less than 7, dielectric loss of less than 0.007, tolerance temperature of 180-300 ℃ and thermal shrinkage of less than 1%.

Drawings

FIG. 1 is a flow chart of a process for preparing a fluorinated polyimide composite membrane by plasma treatment

Advantageous effects

The plasma treated fluorinated polyimide composite membrane is formed by compounding a plasma treated polyimide film and fluorine-containing emulsion. The prepared surface-modified fluorinated polyimide film has a water contact angle of more than 130 degrees, the tensile strength of a composite film coated with the fluorine-containing emulsion is 50-200 MPa, the elongation at break is 10-180%, the elastic modulus is 700-3500 MPa, the water contact angle is more than 100 degrees, the composite film has the characteristics of good insulation, adhesion resistance, static resistance, high and low temperature resistance, corrosion resistance and the like, the dielectric constant is lower than 7, the dielectric loss is lower than 0.007, the tolerance temperature is 180-300 ℃, and the thermal shrinkage rate is lower than 1 percent. Can be used as a diaphragm of a motor, an electric appliance, an electric heating sheet, an electric hair clip, a PTC, a wire cable, an electromagnetic wire and an automobile switch.

Detailed Description

The following examples are given for the detailed implementation and specific operation of the present invention, but the scope of the present invention is not limited to the following examples.