Basic material - Polyimide

Polyimide (polyimide films) is a high temperature, antifriction material. It obtains low rates of friction and creep process. The main purpose: basic material for HDI boards (it is used in combination with reinforced paper and epoxy resin). Polyimide can easily be etched, laser-drilled, metallized. It is quickly processed by chemical methods of creating vias. Colour: from light yellow to bright orange.

Advantages of application

• Thermal and chemical stability.
• A high resistance to mechanical damage.
• After fiber-glass/carbon reinforcement polyimide can be used as a composite.
• High strength characteristics of tension and break.
• A wide temperature operation mode: from -200˚ to + 400˚.
• It is not affected by most solvents/oils, including weak acids, compound alcohol-containing solutions, hydrocarbons, ethers and freons. The only restriction is the application in alkaline and acid (inorganic) media. Resistant to radiation.

The area of application

• Home electronics and portable devices
• Sources of synchronous radiation
• Equipment for high-temperature/high-voltage insulation of electrical circuits
• Flexible and rigid boards

Basic types

• PM-1. It is made from a solution of dimethylformamide by coating. Such films are transparent (the colour varies depending on the thickness of the plate: from light yellow to dark brown). The material has high mechanical and physical properties, retains elasticity in a wide temperature range (from -60˚ to + 220˚).
• PMF is a composite material made on the basis of polyimide PM-1 (30-100 μm thick) and a layer/layers of fluoroplastic (5-10 μm thick). Operation temperatures: from -60˚ to + 200˚, maximum atmosphere pressure is 7 GPa. It can be welded.
• PM-K –electrically-conductive. The material contains microparticles of dispersed soot. It preserves the initial characteristics at temperatures from -200˚ to + 250˚. It can withstand short-term use at + 400˚.
• PM-EU. It has an additional layer of heat-treated protective lacquer. The feature: 2% shrinkage at 350 ° C.
• Non-shrinkage materials. Polyimide is subjected to thermal stabilization during its production. As a result, such material has minimal shrinkage (<0.05%) at + 200 °. It contributes to lamination, gluing and metalizing processes.
• PM-RD. This material as a heat-sealable coating and is produced by repeated application of adhesive lacquers on one or several sides. Then the polyimide undergoes heat treatment.
• PEI –polyetherimide. It is produced with the addition of a polyester solution and n-methylpyrrolidone. It is thermoplastic. Colour: from white to dark grey.
• PM-U –heat shrinkable. It is produced by a high-temperature method of orientation stretching. Shrinkage rates: 2-15%.

 

Specifications

 

Parameters	Values
Breaking strength, MPa	70-180
Relative elongation at break,%	15-90
Modulus of elasticity (tension), MPa	3000-3500
Dielectric capacitivity, kHz	3-3,5
Electric strength, kV/mm	120-270
Dielectric loss angle tangent, kHz	0,0025-0,003
Specific electrical resistance, Ohm m	1014-1015
Heat transfer, W/m K	0,14-0,2
Heat capacity, J/kg K	1014-1015
Index of linear heat expansion, 1015	20-30
Adhesion strength, g/cm	150-250

 

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