Thursday, August 2, 2012

Polyimide - The Ultimate High-Performance Thermoplastic Material

Thermosetting Polyimides (PI) are known for thermal stability, good chemical resistance & excellent mechanical properties. They exhibit very low creep & high tensile strength. These properties are maintained during continuous use to temperatures of 450°F (232°C) and for short excursions, as high as 900°F (482°C).   Professional Plastics offers the widest range of polyimide materials in the industry from Meldin® Shapes, Vespel® Shapes, Kapton® Film, Kaptrex® Film, Cirlex® Laminate, Kaptolam® laminate, Solimide® foam,and Protomid® microbore tubing.

Molded polyimide parts & laminates have very good heat resistance. Normal operating temperatures for such parts and laminates range from cryogenic to those exceeding 500°F (260°C). Polyimides are also inherently resistant to flame combustion and do not usually need to be mixed with flame retardants. Most carry a UL rating of VTM-0.

Polyimide laminates have a flexural strength half life at 480°F (249°C) of 400 hours. Typical polyimide parts are not affected by commonly used solvents & oils — including hydrocarbons, esters, ethers, alcohols and freons. They also resist weak acids but are not recommended for use in environments that contain alkalis or inorganic acids.

Polyimide parts and shapes such as Meldin®, Vespel® are produced via Isostatic Molding, Compression Molding or Direct-Forming.

For more details visit our polyimides webpage at:

Grades of Meldin Polyimide:
MELDIN® 7001, Unfilled Grade
A thermosetting polyimide, MELDIN® 7001 is our unfilled base resin. This grade offers the maximum mechanical properties and high chemical resistance. The MELDIN® 7001 grade is ideal for electrical and thermal insulating applications. More ductile than ceramics, and lighter weight than metals, MELDIN® 7001 is a popular choice for structural parts in aerospace and other applications where metal replacement is desirable.

MELDIN® 7021, 15% by Weight Graphite Filler
Our self-lubricating grade, MELDIN® 7021, has 15% by weight graphite fillers, encapsulated by the base polyimide resin. With its low coefficient of friction and high heat resistance, MELDIN® 7021 provides our customers the best all-around choice for high temperature bearings, seals, and other low-wear applications.

MELDIN® 7211 - 15% Graphite + 10% PTFE Fillers by Weight
MELDIN® 7211 is 15% by weight graphite and 10% by weight PTFE fillers. It has the lowest coefficient of friction of all the MELDIN® 7000 grades. However, above 300°F, we typically use MELDIN® 7021, which has a very similar coefficient of friction to 7211 at temperatures above 300°F, and the wear factor of 7021 is lower than 7211 at temperatures above 300°F.

MELDIN® 7022 - 40% by weight graphite filler
MELDIN® 7022 is 40% by weight graphite filler. It is similar to the 7021 for wear and friction, but it has the best overall dimensional stability (thermally), and the 7022 has the lowest coefficient of thermal expansion – due to the relatively high graphite filler content.

MELDIN® 7003 - 15% molybdenum disulfide lubricating filler
Meldin® 7003 includes 15% molybdenum disulfide lubricating filler for wear applications that operate in a vacuum or in very dry conditions where graphite actually becomes abrasive. Typical applications of Meldin 7003 include seals, bushings, bearings, gears, and other wear surfaces in outer space, ultra-high vacuum or dry gas applications.

Meldin 7000 meets the following specifications :
  • Mil-P-46198 Military Specification (now obsoleted)
  • ASTM D6456-99 Standard Specification
  • SAE AMS 3644G Aerospace Material Specification
  • CPW411 Rev. H Pratt & Whitney Specification
  • MCS 5016 Honeywell Specification
  • UL V0-5VA flammability rating
  • 1 comment:

    1. Polycarbonate provides excellent impact and weather resistance, compared to the average resistance in case of plastics.
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