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Microwave forming method for thermosetting polyimide sheet

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 low production efficiency. Batch molding, easy cracking and delamination, and improved microwave absorption performance

Active Publication Date: 2019-03-26
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 thermosetting polyimide sheet

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, and then at 150 RPM for 15 minutes, take it out use.

[0058] 2), dry

[0059] Put the mixture obtained in step 1) into a nitrogen-protected oven with a furnace temperature of 300°C and dry for 1 hour.

[0060] 3), pre-press

[0061] Add the dried mixture obtained in step 2) into the cavity of a special mold and place it on a press for pre-compression. The first pressure is 30 MPa, the second time is 60 MPa, and the third time is 100MPa, hold the pressure for 8 minutes, lock the special mold, keep the material in the special mold, and wait for use after the pressure is relieved.

[0062] 4), microwave molding

[0063] Put the special mould containing polyimide material in step 3) into the special microwave oven, close the oven door, adjust the microwave frequency to 2450MHZ, ...

Embodiment 2

[0068] 1), mixing

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

[0070] 2), dry

[0071] Put the mixture obtained in step 1) into a nitrogen-protected oven with a furnace temperature of 300°C and dry for 1 hour.

[0072] 3), pre-press

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

[0074] 4), microwave molding

[0075] Put the special mould containing polyimide material in step 3) into the special microwave ov...

Embodiment 3

[0080] 1), mixing

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

[0082] 2), dry

[0083] Put the mixture obtained in step 1) into a nitrogen-protected oven with a furnace temperature of 270° C. and dry for 1 hour.

[0084] 3), pre-press

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

[0086] 4), microwave molding

[0087] Put the special mould containing polyimide material in step 3) into the special...

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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 polymer composite material molding, and specifically relates to a microwave molding method for thermosetting polyimide plates. Background technique [0002] Polyimide refers to a type of polymer containing an imide ring (-CO-NH-CO-) in the main chain, of which polymers containing a phthalimide structure 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. According to the molding process, polyimide can be divided into two types: thermoplasticity and thermosetting. Because the molecular structure of thermosetting polyimide contains repeated aromatic rings and imide groups, the material has excellent mechanical properties, thermal properties, flame retardant properties, dielectric properties, and environmental properties. However, although thermosetting polyimide materials have the above-mentioned exc...

Claims

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Application Information

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Patent Type & Authority Patents(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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