Polyimide resins Vespel

Vespel [Du Pont], TM for fabricated parts, based on polyimide resin and diamond abrasive wheels formulated with a high-temperature polyimide binder. 

Fig. 7.21 A high-pressure electrical leadthrough (L) a brass electrical connector, (M) a vespel (Du Pont polyimide resin) insulating sleeve, (N) a Vespel pressure-sealing sleeve, and (O) a bolt feeding into the bottom of the pressure-vessel cap.

Other physical properties of Vespel (SP-1 polyimide resin) ... 

The aromatic amine di(4-aminophenyl)ether is employed in the manufacture of polyimide film, designated as Kapton (Du Pont). Other commercial materials of this type introduced by Du Pont in the early 1960s included a coating resin (Pyre ML) and a machinable block form (Vespel). In spite of their high price these materials have found established uses because of their exceptional heat resistance and good retention of properties at high temperatures. 

Automotive and electrical/electronics industries are the largest markets for engineering polymers which include Crastin PBT polyesters, Hytrel thermoplastic polyester elastomers, Rynite PET, high-temperature Thermx PCT (polycyclohexylene dimethyl terephthalate), Tribon composites and Tynex filaments, Vespel polyimide parts and shapes, Zenite liquid crystal polymers and Zytel PA resins. In July 2005, DuPont launched the DuPont Vespel SP-202 composition whose properties include the prevention of static charge build-up. Other products include Delrin acetal resins, engineering thermoplastic vulcanisates. Minion mineral reinforced PA resins and Teflon PTFE fluoropolymer resins. 

Thermosetting polyimides are commercially available as uncured resins, thin sheets, and laminates. Thermoplastic polyimides are very often called pseudothermoplastic. There are two general types of polyimides. One type is linear polyimides which are made by combining imides into long chains. Aromatic heterocyclic polyimides are the other usual kind, where R and R" are two carbon atoms of an aromatic ring. Examples of polyimide films include Apical, Kapton, and Kaptrex. Polyimide parts and shapes include Meldin, Vespel, and Plavis. Polyimides have been in mass production since 1955. 

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