Electrical and electronics

A similar effect may be expected from the EU Directive WEEE (Waste Electrical and Electronic Equipment). This aims to control the use of certain materials and to encourage re-use and recycling of all electrical and electronic components (defined as that equipment which is dependant upon electric currents or electromagnetic fields in order to work properly ). For compounders, the immediate implication is to control the use of flame retardants, and a specific aim of the WEEE Directive is to reduce or eliminate halogenated flame retardant additives in the plastics compounds used for E and E products. The deadline for this is 2004, but there will obviously be much discussion as to which FRs should be phased out. 

WEEE will also require products to be certified as containing recycled material. As a result, supply of compounds will need to be certified - as by ISO 9001 certification for compounding. Compounds sourced from recycling of appropriate scrap will be certified as to their content of recyclate, physical properties and colour. The ISO 9000 system will provide the means for auditing, to provide the information required by the WEEE Directive. 

In Europe, the European Commission DGXI set three main objectives in its End of Life Vehicles (ELV) Directive EC 31/7/96. The original dates of implementation were put back by a further two years, after strong representations from the automotive industry  

There is also a strong demand from automobile manufacturers (especially in Germany) to include a percentage of material of proved recycled origin in the new materials that they employ, which will call for testing and quality control facilities at the compounder level. 

---

Sulfur hexafluoride [2551-62-4] 6 molecular weight 146.07, is a colorless, odorless, tasteless gas. It is not flammable and not particularly reactive. Its high chemical stabiUty and excellent electrical characteristics have led to widespread use in various kinds of electrical and electronic equipment such as circuit breakers, capacitors, transformers, microwave components, etc (see Electronic materials). Other properties of the gas have led to limited usage in a variety of unique appHcations ranging from medical appHcations to space research. 

As a tme thermoplastic, FEP copolymer can be melt-processed by extmsion and compression, injection, and blow molding. Films can be heat-bonded and sealed, vacuum-formed, and laminated to various substrates. Chemical inertness and corrosion resistance make FEP highly suitable for chemical services its dielectric and insulating properties favor it for electrical and electronic service and its low frictional properties, mechanical toughness, thermal stabiUty, and nonstick quaUty make it highly suitable for bearings and seals, high temperature components, and nonstick surfaces. 

The most important fields of application for PVDF resias iaclude electric and electronic iadustry products, architectural and specialty finishes, products for the chemical and related iadustries, and rapidly growing specialized uses. 

Electrical. Glasses are used in the electrical and electronic industries as insulators, lamp envelopes, cathode ray tubes, and encapsulators and protectors for microcircuit components, etc. Besides their abiUty to seal to metals and other glasses and to hold a vacuum and resist chemical attack, their electrical properties can be tailored to meet a wide range of needs. Generally, a glass has a high electrical resistivity, a high resistance to dielectric breakdown, and a low power factor and dielectric loss. 

Sheet Miea. Good quahty sheet mica is widely used for many iadustrial appHcations, particularly ia the electrical and electronic iadustries, because of its high dielectric strength, uniform dielectric constant, low power loss (high power factor), high electrical resistivity, and low temperature coefficient (Table 6). Mica also resists temperatures of 600—900°C, and can be easily machined iato strong parts of different si2es and shapes (1). 

Because of its high modulus of elasticity, molybdenum is used in machine-tool accessories such as boring bars and grinding quills. Molybdenum metal also has good thermal-shock resistance because of its low coefficient of thermal expansion combined with high thermal conductivity. This combination accounts for its use in casting dies and in some electrical and electronic appHcations. 

Economic Aspects. PBT is one of the fastest growing commercial thermoplastics. In 1993 the North American market alone exceeded 90,000 t, a 15% increase over 1992 (174). This rapid growth was accounted for mainly by the electrical and electronic and automotive markets, which together accounted for over half the PBT used. The principal manufacturers of PBT in North America, Europe, and Japan are shown in Table 9. 

Electrical Properties. Polysulfones offer excellent electrical insulative capabiUties and other electrical properties as can be seen from the data in Table 7. The resins exhibit low dielectric constants and dissipation factors even in the GH2 (microwave) frequency range. This performance is retained over a wide temperature range and has permitted appHcations such as printed wiring board substrates, electronic connectors, lighting sockets, business machine components, and automotive fuse housings, to name a few. The desirable electrical properties along with the inherent flame retardancy of polysulfones make these polymers prime candidates in many high temperature electrical and electronic appHcations. 

Polysulfones also offer desirable properties for cookware appHcations, eg, microwave transparency and environmental resistance to most common detergents. Resistance to various sterilizing media (eg, steam, disinfectants, and gamma radiation) makes polysulfones the resin family of choice for many medical devices. Uses in the electrical and electronic industry include printed circuit boards, circuit breaker components, connectors, sockets, and business machine parts, to mention a few. The good clarity of PSF makes it attractive for food service and food processing uses. Examples of appHcations in this area include coffee decanters and automated dairy processing components. 

J. A. Oberteuffer, Magnetic Separation M Kevieiv of Principles, Devices and Applications, Institute of Electrical and Electronics Engineers, Inc., 1977. P. A. Cliermemnykli and I. V. Kurchatov, IEEE Trans. Magnetics, 28(1), 651—658 (Jan. 1992). 

A.merican National Standardfor Metric Practice, ANSI/IEEE Std 268-1992, Institute of Electrical and Electronics Engineers, Inc., New York, 1992. 

Electrical and Electronic. Diamond is an electrical insulator (-- lO H/cm) unless doped with boron when it becomes ap-ty e semiconductor with a resistivity in the range of 10 to 100 Q/cm. n-Ty e doping has often been claimed but is less certainly estabUshed. The dielectric constant of diamond is 5.58. 

Includes paints and poHshes, antiknock and other compounds, soldering and/or welding, electrical and electronic products, mechanical products, magnetic tape, small packages, industrial diamonds, and drilling mud. 

Electrical and Electronic Applications. Silver neodecanoate [62804-19-7] has been used in the preparation of a capacitor-end termination composition (110), lead and stannous neodecanoate have been used in circuit-board fabrication (111), and stannous neodecanoate has been used to form patterned semiconductive tin oxide films (112). The silver salt has also been used in the preparation of ceramic superconductors (113). Neodecanoate salts of barium, copper, yttrium, and europium have been used to prepare superconducting films and patterned thin-fHm superconductors. To prepare these materials, the metal salts are deposited on a substrate, then decomposed by heat to give the thin film (114—116) or by a focused beam (electron, ion, or laser) to give the patterned thin film (117,118). The resulting films exhibit superconductivity above Hquid nitrogen temperatures. 

A. Ehrhch, IEEE Proceedings of the 9th Electrical Insulation Conference, Sept. 8—11,1969, Institute of Electrical and Electronic Engineers, Piscataway, N.J.,pp. 56-60. 

In the broad range of ceramic materials that are used for electrical and electronic apphcations, each category of material exhibits unique property characteristics which directiy reflect composition, processing, and microstmcture. Detailed treatment is given primarily to those property characteristics relating to insulation behavior and electrical conduction processes. Further details concerning the more specialized electrical behavior in ceramic materials, eg, polarization, dielectric, ferroelectric, piezoelectric, electrooptic, and magnetic phenomena, are covered in References 1—9. 

Eor more demanding uses at higher temperatures, for example, in aircraft and aerospace and certain electrical and electronic appHcations, multifunctional epoxy resin systems based on epoxy novolac resins and the tetraglycidyl amine of methylenedianiline are used. The tetraglycidyl amine of methylenedianiline is currently the epoxy resin most often used in advance composites. Tetraglycidyl methylenedianiline [28768-32-3] (TGALDA) cured with diamino diphenyl sulfone [80-08-0] (DDS) was the first system to meet the performance requirements of the aerospace industry and is still used extensively. 

Stress Relaxation. Copper alloys are used extensively in appHcations where they are subjected to moderately elevated temperatures while under load. An important example is the spring member for contacts in electrical and electronic coimectors. Critical to rehable performance is the maintenance of adequate contact force, or stabiUty, while in service. Excessive decrease in this force to below a minimum threshold value because of losses in spring property can lead to premature open-circuit failure (see Electrical connectors). 

---