Reinforced Gasketing Material

Further reduction in deformation can be obtained by alternately inserting perforated stainless steel plates (Fig. 3.3) between the oriented sheets prior to sintering.The sintering process is conducted under pressure to consolidate the composite and obtain a predetermined thickness. At the end of sintering, the composite is cooled rapidly underpressure. PTFE actually bonds to stainless steel in this process. The decrease in creep is often substantial for example, by insertion of two steel plates, the creep relaxation of a silica-filled PTFE is decreased from 57.9% to 30.5% at 100°C.[i ] 

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CF. [Qistom Fibers] Cellulose fibers reinforcing filler and vise, control agent for epoxy grouts, gasket material, mastics as asbestos replacement... 

Hannesen [6] points out that the choice of gasket material depends on the type of flange face in use. With raised-face flanges, he names aramid fiber as a possible replacement for asbestos in dry chlorine service. With liquid chlorine, aramid should be confined by a metal envelope. With tongue-and-groove flanges, metal-reinforced... 

RT/Duroid M. [Rogers] FIFE, glass-reinforced wear-resistant material for seats, seals, bearings fm chemical and food processing equip., backup rings in hydraulic service, rub strips in B-IB bomber, mictowave dielec, diermal insulation, clutch face gaskets. 

MAJOR USES Used in paper products, building materials, textiles, asbestos-cement products, gaskets, valves, clutch/transmission components, molten glass handling equipment, chemical tanks, electrical switchboards, cooling tower components, roofing compositions, packaging, pipes, ducts, floor tiles, reinforced plastics and rubber, insulation, paint filler, fireproof fabrics. 

Application of fluorosihcone elastomers is also found in the field of lubricants for pumps and compressors, where harsh chemical solvents are generally used. Moreover, because the fluorosihcone rubbers are fuel-resistant, these materials are extensively used in the automotive and aerospace industries to make 0-rings, gaskets, washers, sealants, EGR diaphragms, etc. A blend of poly(vinylidene fluoride) with a fluorosihcone elastomer was prepared by Mascia et al. [38], with the idea that the vinylidene fluoride would reinforce the thermomechanical properties of the fluorosihcone polymer. This idea was proven to be fruitful and the polymer had a peak melting temperature of approximately 120°C. 

The new elastomers are particularly relevant to the automotive industry because they offer better properties - particularly heat, oil and fuel resistance - than the established materials such as natural and synthetic rubber and plasticized PVC. Among the most important types are PUR elastomers, PBT block copolymers, EPDM olefinic terpolymers and ethylene-acrylic elastomers. Typical applications are the traditional rubbery ones of gaskets, seals, gaiters and cable covers, but set in the aggressive underbonnet environment of today s performance vehicles. Beyond this, however, there are examples where these materials are sufficiently versatile to have been selected, sometimes with reinforcement, as engineering components in their own right. 

Polyurethane is subject to hydrolic degradation at its higher temperature limits. Polyurethane is machinable. It does not seal as well as rubber, and additional 0-rings and gaskets are needed when switching from rubber to polyurethane lined parts. Polyurethane is available in thermoset and thermoplastic forms. A new generation of glass-reinforced polyurethane thermoplastic materials are available from different manufacturers. The properties of polyurethane are presented in Tables 10-17 and 10-18. 

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