Preparation method for polyimide three-layer composite film with electromagnetic shielding function

Abstract

The invention provides a preparation method for a polyimide three-layer composite film with an electromagnetic shielding function. When carbon nanotubes are employed for modification of a polyimide film, the resistivity of the polyimide film can be effectively reduced; however, with increase of the content of the carbon nanotubes, the carbon nanotubes are substantially agglomerate in polyimide, which leads to drastic decrease of the mechanical properties of the polyimide film. The preparation method provided by the invention comprises the following steps: (1) preparation of a carbon nanotube-modified polyamide acid solution; (2) preparation of a carbon nanotube-modified polyamide acid microporous film by using an electrostatic spinning method; (3) preparation of a polyamide acid solution; (4) coating of two sides of the microporous film with the polyamide acid solution; and (5) thermal imidization of a prepared carbon nanotube-modified polyimide acid three-layer composite film. The polyimide three-layer composite film prepared in the invention is mainly applied to broaden the application scope of polyimide films in the field of electromagnetic shielding materials.

Description

[0001] Technical field:

[0002] The invention relates to a preparation method of a polyimide three-layer composite film with electromagnetic shielding function.

[0003] Background technique:

[0004] Polyimide (PI) is a class of high-performance polymer materials characterized by imide rings. It has high heat resistance and excellent mechanical properties, electrical properties, radiation resistance, solvent resistance, etc. , as a dielectric space layer, metal thin film protective layer is widely used in the field of microelectronics, but polyimide has excellent insulation performance and high resistivity, so it needs to be modified by adding conductive fillers to reduce its resistivity and then can be used as electromagnetic shielding material used. In recent years, conductive fillers such as silver nanowires, carbon nanotubes, carbon fibers, and polyaniline have been widely used as fillers to fill polyimide matrices to prepare polyimide films with electromagnetic shieldin...

Examples

Embodiment 1

[0024] A preparation method of a polyimide three-layer composite film with electromagnetic shielding function is characterized in that: the method comprises the steps of:

[0025] (1) Preparation of carbon nanotube modified polyamic acid solution;

[0026] (2) Preparation of carbon nanotube-modified polyamic acid microporous membrane by electrospinning;

[0027] (3) Preparation of polyamic acid solution;

[0028] (4) Coating polyamic acid solution on both sides of the microporous membrane;

[0029] (5) Thermal imidization of carbon nanotube-modified polyamic acid three-layer composite film.

Embodiment 2

[0031] According to the preparation method of the polyimide three-layer composite film with electromagnetic shielding function described in Example 1, it is characterized in that: the preparation of the carbon nanotube modified homo-phenylene polyamic acid solution is weighed in a molar ratio of 1:1.02 Get 4,4-diaminodiphenyl ether and pyromellitic dianhydride, pour 4,4-diaminodiphenyl ether and 0-10wt% single-walled carbon nanotubes into a three-necked flask, and The acid solid content is 26wt%, add N,N-dimethylacetamide, pass through nitrogen for protection, and after ultrasonic stirring in a cold water bath at 10°C for 1 h, remove the ultrasonic, and weigh the pyromellitic dianhydride in batches Gradually add to the solution, and the feeding time is controlled at 120 minutes. After the rod climbing phenomenon occurs, continue to stir for 24 hours. Pour the viscous carbon nanotube modified polyamic acid liquid into a small beaker and seal it for later use.

Embodiment 3

[0033] According to the preparation method of the polyimide three-layer composite film with electromagnetic shielding function described in embodiment 1 or 2, it is characterized in that: described electrospinning method prepares carbon nanotube / polyamic acid microporous membrane, takes A certain amount of the carbon nanotube modified polyamic acid liquid is placed in the syringe pump of the electrospinning device, the spinning voltage is adjusted to 10kV, the injection speed is 0.3ml / h, the receiving distance is 15cm, and the spinning is made for 5 h A carbon nanotube modified polyamic acid microporous membrane with a thickness of 20 μm.

[0001] Technical field:

[0002] The invention relates to a preparation method of a polyimide three-layer composite film with electromagnetic shielding function.

[0003] Background technique:

[0004] Polyimide (PI) is a class of high-performance polymer materials characterized by imide rings. It has high heat resistance and excellent mechanical properties, electrical properties, radiation resistance, solvent resistance, etc. , as a dielectric space layer, metal thin film protective layer is widely used in the field of microelectronics, but polyimide has excellent insulation performance and high resistivity, so it needs to be modified by adding conductive fillers to reduce its resistivity and then can be used as electromagnetic shielding material used. In recent years, conductive fillers such as silver nanowires, carbon nanotubes, carbon fibers, and polyaniline have been widely used as fillers to fill polyimide matrices to prepare polyimide films with electromagnetic shieldin...

Examples

Embodiment 1

[0024] A preparation method of a polyimide three-layer composite film with electromagnetic shielding function is characterized in that: the method comprises the steps of:

[0025] (1) Preparation of carbon nanotube modified polyamic acid solution;

[0026] (2) Preparation of carbon nanotube-modified polyamic acid microporous membrane by electrospinning;

[0027] (3) Preparation of polyamic acid solution;

[0028] (4) Coating polyamic acid solution on both sides of the microporous membrane;

[0029] (5) Thermal imidization of carbon nanotube-modified polyamic acid three-layer composite film.

Embodiment 2

[0031] According to the preparation method of the polyimide three-layer composite film with electromagnetic shielding function described in Example 1, it is characterized in that: the preparation of the carbon nanotube modified homo-phenylene polyamic acid solution is weighed in a molar ratio of 1:1.02 Get 4,4-diaminodiphenyl ether and pyromellitic dianhydride, pour 4,4-diaminodiphenyl ether and 0-10wt% single-walled carbon nanotubes into a three-necked flask, and The acid solid content is 26wt%, add N,N-dimethylacetamide, pass through nitrogen for protection, and after ultrasonic stirring in a cold water bath at 10°C for 1 h, remove the ultrasonic, and weigh the pyromellitic dianhydride in batches Gradually add to the solution, and the feeding time is controlled at 120 minutes. After the rod climbing phenomenon occurs, continue to stir for 24 hours. Pour the viscous carbon nanotube modified polyamic acid liquid into a small beaker and seal it for later use.

Embodiment 3

[0033] According to the preparation method of the polyimide three-layer composite film with electromagnetic shielding function described in embodiment 1 or 2, it is characterized in that: described electrospinning method prepares carbon nanotube / polyamic acid microporous membrane, takes A certain amount of the carbon nanotube modified polyamic acid liquid is placed in the syringe pump of the electrospinning device, the spinning voltage is adjusted to 10kV, the injection speed is 0.3ml / h, the receiving distance is 15cm, and the spinning is made for 5 h A carbon nanotube modified polyamic acid microporous membrane with a thickness of 20 μm.