Automotive seal requirements

Enichem and DuPont ate two suppHers of acryHc elastomers. It is estimated there ate - 9000 t/yr of these elastomers used in the United States. The principal uses of acryHc elastomers ate in automotive appHcations requiring both oil and heat resistance. These include transmission, valve stem, crankshaft, pinion, and odpan gaskets and seals. In addition hose, tubing, toUs, and belts ate made from acryHc polymers. 

TPV applications are mainly in automotive seals and pipe seals where a good compression set and heat resistance are required. 

Numerous seal designs are available to the automotive chemist. Choices are made depending on the application and sealing requirements. Figure 8.16 shows a few of the types of seal designs used. 

Fluid engine mounts (Figure 2.1) for the aerospace industry and automotive hydromounts require the bonded rubber to act as both a seal for the fluid and as a spring component... 

Lead-acid batteries can be classified into three major types or categories, namely, automotive (SLI), stationary, and motive power (industrial). In addition, there are many special batteries that cannot be easily categorized as either of the above types. As these types of batteries are constructed with different materials and design to meet the requirements of their intended end uses, each requires a particular separator with specific material composition, mechanical design, and physical, chemical, and electrochemical properties that are tailored for the battery and its relevant specific uses. These batteries are generally available in flooded electrolyte or valve regulated (sealed) versions. In this section the types... 

Adhesives and Sealants. Dominated by copolymers, adhesives and sealants remain somewhat of a specialty market. These polymers usually contain high copolymer content and low viscosity, and often require blending with oilier compounds prior to final application. Their uses are numerous, e.g., as seals for bottled drinks, as tie layers between incompatible polymers, or as automotive adhesives... 

The use of aromatic compounds in automotive fuels, higher under-the-hood temperatures, combined with automotive regulations, presents a challenge for the rubber parts (e.g., hose, seals, diaphragms) used in vehicles. Traditional elastomers do not have high enough resistance to meet all these requirements, but fluorocarbon... 

Engineering polymers for high-temperature and -pressure applications are in use extensively in original equipment manufacturers around the world. The high-strength properties of these materials are necessary to obtain the desired mass reductions, efficiency, cost, and performance required in today s market. In current automotive applications, several polymers predominate for thermoplastic seals, thrust washers, intake manifolds, and other components. 

Fig. 7.8.7 shows the development steps of the Bosch camera module. A stereo video camera for automotive application can be produced as a compact unit to be mounted at the upper rim of the front window of the car. Fig. 7.8.8 shows the unit. It consists of two camera heads with a nonlinear CMOS sensor each, and the camera optics, both mounted into a housing, which can be hermetically sealed. The camera heads are connected to a powerful computer for image processing. The power required depends on the functions. 

The major use of SBR is in the production of tires, particularly passenger-car and light-truck tires, and in other automotive applications where SBR is blended with other elastomers. These applications include belts, hoses, seals, and various extruded and molded items. Nontire and nonautomotive uses of SBR are in industries that require hoses, belts, gaskets, or seals. Others include footwear (shoe soles) various kinds of solid wheels roll covers coated fabrics and electrical (wire and cable) insulation. 

Reinforced PTFE applications include bushings and seals in compressor hydraulic applications, automotive applications, and pipe liners. A variety of moldings are used in aircraft and missiles and also in other applications where use at elevated temperatures is required. 

Qualihcation tests for adhesives are dehned in Method 5011 of MlL-STD-883 and requirements for qualifying sealed hybrid microcircuits or multichip modules that contain adhesives are specihed in MlL-PRF-38534. Space, automotive, and medical applications generally use the military specihcations, but are modihed or supplemented with additional tests and requirements for their particular application. 

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