MAXTIDE MACHINERY CO., LTD.

Physical Properties and Applications of Polyimide (PI) and Polyte

Polyimide (PI) Product physical properties and applications:

 

1. Resistant to Ultra High and Low Temperature

 

Working temperature: -272 ~ +360 °C

Instantaneous application of high temperature: Up to +500 °C.

 

2. Abrasion Resistance

 

The PV threshold value of non-lubricating conditions is more than 10 times of general engineering plastics, and can resist strong impact and shaking wear.

 

3. Resistance to deformation and creep

PI does not soften at high temperatures and can withstand high loads.  The creep age at 1,000 ° C at 18.2 Mpa is only 0.6%.

 

4. Resistant to plasma and various rays.

 

5. Ultra-vacuum application

 

Excellent sealing, and reach 10-10 Torr..

 

PI is widely used in aircraft, aviation, automotive, office equipment, electrical and electronic equipment, scientific instruments, industrial machinery and production equipment industries, which require temperature resistance, wear resistance, sealing, dimensional stability and deformation, and the product contains a sealing ring, thrust washers, plain bearings, vacuum pump blades, valve seats, gears, etc.

 

Polyimide products can be easily divided into virgin PI products and PI composite products:

 

1. Virgin PI Products

 

100% pure polyimide resin can be molded, injection molded, extruded, with excellent overall performance, high mechanical properties, excellent electrical and thermal insulation properties, high temperature resistance, high wear resistance (high PV value) and excellent dimensional stability. The product application mainly includes the high requirements of mechanical properties, purity, insulation and friction coefficient.  Typical applications include valve seat, mold insulation cap, plasma torch vortex ring, timing gear tensioner, printer paper, separation claws, brake pad sensing positioners, etc..

 

2. PI Composite Products

 

2-1 PI and PTFE Composite Products

 

It is molded with 15% Polytetrafluoroethylene (PTFE) and polyimide (PI) resin to improve the wear resistance of the product and make the size more stable. Typical applications include high temperature seals, support rings, guide wear rings, compressor piston rings, heat resistant gears, etc., which can be assembled to products like the gear pumps and copiers.

 

2-2 PI and Graphite Composite Products

 

Molded with 15% graphite and polyimide (PI) resin, PI composite products will have excellent wear resistance under high PV conditions. Product applications include a variety of seal rings and seals, a variety of plain bearings.  Typical applications include thrust washers of auto transmissions, seal rings, piston rings, hydraulic pump seal rings, EGR automotive exhaust recovery bushings, turbocharger bushing cages, miniature dental bushing cages, vacuum pumps and pneumatic tool blades.

 

Molded with 40% graphite and polyimide (PI) resin, PI composite products will have very low linear expansion and friction coefficients, and will be suitable for a wide working temperature and high dimensional stability requirements for parts.  For example, high pressure seal rings and gasket can be used to make hydraulic pumps and hydraulic booster.

 

2-3 PI, Graphite and PTFE Composite Products

 

Molded with 15% graphite, 10% PTFE and polyimide (PI) resin, composite material products will have a very low coefficient of friction and is suitable for high speed applications.  The main application of the product is the piston sealing ring.  Due to its excellent wear resistance and dimensional stability, it has extremely high reliability to seal gas.

 

2-4 PI and Molybdenum Disulfide Composite Products

 

Molded with 15% molybdenum disulfide and polyimide (PI) resin, composite material products will have excellent wear resistance and sealing performance under high vacuum environment, suitable to make valve seats and bayonet for the applications in ultra-vacuum and outer space environments.

 

Composites of PI and molybdenum disulfide are also widely used in centrifugal pumps for the industries like refineries, chemical plants, power plants and other fluid processing equipment. The composite material can be used as the mouth ring, throat bushing and bearing of pumps.  It can replace other composite materials, such as metal, graphite and silicon carbide, to significantly improve the efficiency and reliability of the pump.  The probability of a stuck pump during operation can be reduced by more than 50%.

 

2-5 PI and Diamond Resin Composite Products:

 

Ultra-fine polyimide (PI) resin can be used as a bonding agent for diamond grinding wheel and heavy-duty resin grinding wheel.  It does not produce low molecular volatiles during curing.  It has good compatibility with various fillers, high bonding strength and unique flexibility.  It can withstand the test of large cutting tool feeding.  The production efficiency is 35~50% higher than that of phenolic resin grinding wheel, and the service life time is 2 times more.  Because of its excellent wear resistance, heat resistance, moderate melt flow and convenient molding and processing, it is widely used in production processes that require high strength, high and low temperature resistance, high electrical insulation and self-lubricating for machinery and aerospace parts.

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