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Microwave forming method for thermoset polyimide panels

A polyimide and molding method technology, which is applied in the field of microwave molding of thermosetting polyimide sheets, can solve the problems of wear resistance and mechanical properties that cannot meet the requirements of use, uneven heating of materials, and cold center of products. The effect of batch molding, solving easy cracking and delamination, and improving wave absorbing performance

Active Publication Date: 2017-09-08
HEFEI GENERAL MACHINERY RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the most widely used forming method for thermosetting polyimide sheets is the electric heating forming method. However, since electric heating is transferred to the polyimide material by an external heat source such as a metal mold or heated gas, it is easy to cause uneven heating inside and outside the material. The "cold center" phenomenon of the product will cause delamination or cracking of the formed sheet, and the wear resistance and mechanical properties cannot meet the use requirements
In addition, the electric heating forming method also has problems such as large power consumption, long time consumption, and low production efficiency.

Method used

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  • Microwave forming method for thermoset polyimide panels

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0056] 1), mixing

[0057] Weigh 10 parts by weight of copper calcium titanate powder and 50 parts by weight of thermosetting polyimide powder, add them to a three-dimensional mixer, stir at 300 RPM for 10 minutes, then stir at 150 RPM for 15 minutes, take out the use.

[0058] 2), drying

[0059] The mixture obtained in step 1) was put into a nitrogen-protected oven with a furnace temperature of 300° C., and dried for 1 hour.

[0060] 3), pre-compression

[0061] Add the dried mixture obtained in step 2) into the cavity of a special mold, put it on a press for pre-compression, pressurize to 30MPa for the first time, pressurize for the second time to 60MPa, and pressurize for the third time to 100MPa, keep the pressure for 8 minutes, lock the special mold, and keep the material in the special mold. After the pressure is released, it is ready for use.

[0062] 4), microwave molding

[0063] Put the special mold with polyimide material in step 3) into a special microwave ov...

Embodiment 2

[0068] 1), mixing

[0069] Weigh 35 parts by weight of calcium copper titanate powder, 15 parts by weight of ground carbon fiber powder, and 90 parts by weight of thermosetting polyimide powder, add it to a three-dimensional mixer, stir for 5 minutes at a speed of 500 RPM, and then Stir at 200 RPM for 10 minutes, take it out for use.

[0070] 2), drying

[0071] The mixture obtained in step 1) was put into a nitrogen-protected oven with a furnace temperature of 300° C., and dried for 1 hour.

[0072] 3), pre-compression

[0073] Add the dried mixture obtained in step 2) into the mold cavity of a special mold, put it on a press for pre-compression, pressurize to 40MPa for the first time, pressurize for the second time to 100MPa, and pressurize for the third time to 150MPa, keep the pressure for 15 minutes, lock the special mold, keep the material in the special mold, and wait for use after the pressure is released.

[0074] 4), microwave forming

[0075] Put the special mo...

Embodiment 3

[0080] 1), mixing

[0081] Weigh 15 parts by weight of calcium copper titanate powder, 35 parts by weight of ground carbon fiber powder, and 60 parts by weight of thermosetting polyimide powder, add it to a three-dimensional mixer, stir at 400RPM for 5 minutes, and then Stir at 100 RPM for 15 minutes, take it out for use.

[0082] 2), drying

[0083] The mixture obtained in step 1) was put into a nitrogen-protected oven with a furnace temperature of 270° C., and dried for 1 hour.

[0084] 3), pre-compression

[0085] Add the dried mixture obtained in step 2) into the cavity of a special mold, put it on a press for pre-compression, pressurize to 40MPa for the first time, pressurize for the second time to 60MPa, and pressurize for the third time to 120MPa, keep the pressure for 10 minutes, lock the special mold, keep the material in the special mold, and wait for use after the pressure is released.

[0086] 4), microwave forming

[0087] Put the special mold with polyimide ...

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Abstract

The invention belongs to the technical field of macromolecule composite material forming, and particularly relates to a microwave forming method for thermoset polyimide panels. The method comprises the steps that firstly, a certain weight part of ferroelectric ceramic powder, a certain weight part of ground carbon fiber powder and a certain weight part of thermoset polyimide powder are weighed, the above raw materials are added in a stirring machine to be subjected to dry method mixing, and pre-pressing is conducted on a cold press; then the raw materials are placed in a microwave oven along with a special die, microwave heat forming is conducted, then the raw materials are placed on a hot press to be subjected to hot press shaping, then, demoulding treatment is conducted, and the thermoset polyimide panels meeting the requirement can be obtained. The method has the beneficial effects that the technology is simple, equipment is environment-friendly, energy and electricity saving is achieved, and operation is easy; and it can be guaranteed that various properties of the formed polyimide materials can meet the using requirement, and the production efficiency and the quality stability of the thermoset polyimide panels can be greatly improved.

Description

technical field [0001] The invention belongs to the technical field of forming polymer composite materials, and in particular relates to a microwave forming method for thermosetting polyimide plates. Background technique [0002] Polyimide refers to a class of polymers containing imide rings (-CO-NH-CO-) on the main chain, among which polymers containing phthalimide structures are the most important. As a special engineering material, polyimide was listed as one of the most promising engineering plastics in the 21st century in the 1960s. Polyimide can be divided into two types according to the molding process: thermoplastic and thermosetting. Due to the repeated aromatic rings and imide groups in the molecular structure of thermosetting polyimide, the material has excellent mechanical properties, thermal properties, flame retardant properties, dielectric properties, environmental properties, etc. However, although thermosetting polyimide materials have the above-mentioned ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B29C43/14B29C43/36B29C43/52B29C43/58B29C35/08C08L79/08C08K7/06C08K3/24
CPCB29C35/08B29C43/14B29C43/36B29C43/52B29C43/58B29C2035/0855B29C2043/5816C08K3/24C08K7/06C08K2201/003C08K2201/014C08K2201/016C08L79/08
Inventor 李鲲杨家义杨博峰郑国运姚黎明李凤成王永乐沈宗沼李香丁思云吴萍蔡粤华吴兆山
Owner HEFEI GENERAL MACHINERY RES INST
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