Automotive seal materials

This material finds use as a sealing material in automotive applications and marine motor lead wire insulation. It has also been used as the base polymer for low flammability, halogen free, cable jacketing compounds. 

Nitto Denko Corporation primarily manufactures industrial adhesive tapes for the electronics, automotive, health care, packaging and construction industries. The company produces industrial, electronic and functional products. Industrial products include double-coated adhesive tapes, masking tapes surface protective materials, sealing materials and label printing systems. Electronics products include LCD-related items general and advanced device resins printed circuit boards and semiconductor package adhesive sheets. Functional products include medical items such as transdermal therapeutic patches polymer separation membranes used for water purification and treatment and plastic engineering products such as information equipment and porous film materials used in cars, electronics, and home appliances. Nitto Denko America, Inc., an optoelectronics subsidiary, manufactures semiconductor... 

An automotive seal, for instance, must be efficient that is, it must have the ability to expand against a sealing surface quickly. This efficiency is related to the elastic modulus of the material, which is related to its stiffness [1], The elastic modulus is the ratio of stress to corresponding strain in a material below the proportional limit on a... 

The thermal serviceability or usage range is the temperature range in which a sealing material can be used and expected to function without degradation of properties. Table 8.1 shows the ranges of some compounds typically used in automotive sealing. 

Riga [8] used TG and TMA for quality control of automotive elastomeric seals. TMA was used to confirm the Tg of the polymer, as well as the thermal expansion coefBcient. TG was also used to provide data on the composition of the compounded seal material. Both of these techniques provide critical information for control of quality but it was pointed out that these techniques alone coidd not predict failure of the seals unless a very specific problem was pointed out. 

Automotive seals and gaskets in hot oil applications comprise a major market for these materials. Acrylic rubbers can be compounded in a Banbury mixer and fabricated by injection molding, compression molding, resin transfer molding, extrusion, and calendering. 

Multi-shot moulding techniques are well established, their growth being pushed by the development of thermoplastic elastomer (TPE) materials, enabling rigid and flexible material combinations such as those described previously to be employed. These can also be seen in a variety of other applications from automotive seals to bras. 

These thermoplastic natural mbber elastomers have a place in the modem world, where recycling has become so important, and when excessive heat is not found in service. Thus, footwear, gla2ing seals, sports goods, hose, domestic products, and a whole range of automotive products have already been identified for such use. It must be noted, however, that tines are not a potential market for these materials, because of the high temperatures which result from emergency braking. 

The excellent properties of these fluoroelastomers come with a high price tag. Kalrez, for example, is extremely expensive ( 33—44/kg). These materials are used in automotive appHcations (seals, gaskets, fuel hose lines, engine parts, etc), where they can withstand under-hood temperatures. They are also used in equipment for oil and gas production and chemical processing. U.S. consumption in 1988 was 3100 t (76). 

Material Trends of Automotive Elastomer Parts (Seals)... 

Polyurethanes are used in a wide variety of applications, seals, metal forming dies, liners, coupling elements, rollers, wheels and conveyor belts being examples. The thermoplastic polyurethanes are used as cable jacketing materials, conduits, fabric coatings, in ski boots and other rigid boot soles, automotive body components, gear wheels and other business machine parts. 

New polymer structures allow the control of processability and final characteristics. For example, Mitsui is launching nanostructured metallocene alpha-olefins that have a crystallite size of the order of nanometres instead of microns as for conventional metallocene polyolefins. This yields a better balance of transparency, heat resistance, flexibility and elasticity characteristics. Targeted applications are automotive interior trim, packaging film, construction materials, protective films for electronic and optical parts, sealing products and as polymer modifiers. 

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... 

Polybenzimidazoles have been used for seals, mechanical components, electrical connectors, valve scats, and as components ofmatcrials-handling equipment in the petrochemical, geothermal, chemical process, aerospace, defense, automotive, and electrical products industries. These materials frequently are procured as replacement parts for other materials in an effort to improve equipment performance. 

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