Insulating compound

MIE-I-46058C(6f Insulating Compound, Electrical for CoatingPrinted Circuit-Assemblies), U.S. Dept, of Defense, Washington, D.C., Nov. 8, 1982. 

Union Carbide Corp., Kabelitems Wire and Cables No. 160, Eong-life Insulation Compounds Update, Danbury, Conn. 

The toxicity of chloronaphthalenes requires that special attention and caution be used during their manufacture and use acne is the most common result of excessive skin exposure to them and the most frequendy affected areas are the face and neck (16). Liver damage has occurred in workers who have been exposed repeatedly to vapors, particulady to those of penta- and hexachloronaphthalene [1335-87-1] (17,18). Uses for the chlorinated naphthalenes include solvents, gauge and instmment duids, capacitor impregnants, components in electric insulating compounds, and electroplating stop-off compounds. 

By reactive sputtering, many complex compounds can be formed from relatively easy-to-fabricate metal targets, insulating compounds can be deposited using a d-c power supply, and graded compositions can be formed, as described. The process, however, is compHcated. 

The apex (often referred to as bead filler) compound must be formulated for excellent dynamic stiffness to facilitate stress distribution and provide good car handling properties. The bead insulation compound must possess good adhesion to this most important component for enclosing the pHes of the tire and holding the tine to the rim. The chafer/rim strip compound protects the pHes from rim abrasion and seals the tire to the rim. 

For this reason tribasic lead sulphate, a good heat stabiliser which gives polymer compounds with better electrical insulation properties than lead carbonate, has increased in popularity in recent years at the expense of white lead. Its weight cost is somewhat higher than that of lead carbonate but less than most other stabilisers. This material is used widely in rigid compounds, in electrical insulation compounds and in general purpose formulations. 

The few formulations given below are intended as a general guide. They should not be taken as recommendations for a specific application where many factors, not considered in the brief discussion here, would need to be taken into account. Formula 1 gives a typical general purpose insulation compound. 

Dioxime cures yield vulcanisates with good ozone resistance and moisture impermeability and, as such, are frequently used for curing electrical insulating compounds. 

Several classes of potentially useful fluorescent materials exist. Most lamp phosphors and many solid state materials are insulating compounds containing ionic activators. The spectra of the rare-earth activators resemble, to a first approximation,... 

The choice of sensor material determines range, sensitivity, and stability. By considering the latter factors, it is found that inorganic insulating compounds, such as most lamp phosphors and many solid state laser materials, are the most suitable materials for thermometric applications. Indeed, these materials are most commonly used in the existing commercial fluorescence thermometer schemes. 

In this equation, aua represents the product of the coefficient of electron transfer (a) by the number of electrons (na) involved in the rate-determining step, n the total number of electrons involved in the electrochemical reaction, k the heterogeneous electrochemical rate constant at the zero potential, D the coefficient of diffusion of the electroactive species, and c the concentration of the same in the bulk of the solution. The initial potential is E/ and G represents a numerical constant. This equation predicts a linear variation of the logarithm of the current. In/, on the applied potential, E, which can easily be compared with experimental current-potential curves in linear potential scan and cyclic voltammetries. This type of dependence between current and potential does not apply to electron transfer processes with coupled chemical reactions [186]. In several cases, however, linear In/ vs. E plots can be approached in the rising portion of voltammetric curves for the solid-state electron transfer processes involving species immobilized on the electrode surface [131, 187-191], reductive/oxidative dissolution of metallic deposits [79], and reductive/oxidative dissolution of insulating compounds [147,148]. Thus, linear potential scan voltammograms for surface-confined electroactive species verify [79]... 

A not unrelated definition of a for sp-valent octet AB compounds has been given by Phillips and Van Vechten (1969). These octet compounds such as NaCl and ZnS have eight valence s and p electrons per AB unit Phillips and Van Vechten assumed that the average energy gap E% of these semiconducting or insulating compounds is made up of covalent and ionic contributions, Ec and E respectively, that are related via eqn (3.20) by... 

Next let us discuss the electronic defects associated with point defects in semiconductive or insulating compounds, which lead to non-stoichiometry. Consider a NiO crystal, which has a NaCl-type structure, as NiO can be regarded as an ionic crystal, the valence states of Ni and O are Ni and O , respectively. We assume that the non-stoichiometry originates only from metal vacancies. Generation of metal defects in NiO may be expressed by a chemical reaction similar to eqn (1.119), i.e. 

For each specific application of a rubber compound as an insulating material, there is a minimum value of resistivity below which it does not function satisfactorily. In addition, insulating compounds are required to withstand the effect of water, moist atmosphere, or heat without their resistivity values falling below a satisfactory level. Insulation resistance measurements frequently serve as useful control tests to detect impurities and manufacturing defects in rubber products. 

Diamine Dielectric strength Organic compound containing two NH2 groups. The measure of polyurethane s ability as an insulating compound to resist the passage of a disruptive discharge produced by an electric potential. 

A probability function was proposed to screen the single wire bum flame spread using heat release capacity measured by PCFC on halogen-free FR compounds.143 Figure 26.4 shows the probability of flame spread for a single wire bum as a function of heat release capacities of wire insulation compounds. It was suggested that the probability of flame spread for an insulated wire is less than 5% when the heat release capacity is less than ca. 320J/g K. 

Biocides. The attack of fungi on the several components of a vinyl formulation may manifest itself as an unsightly growth looking much like dirt or may result in the formation of discolored areas (yellow, pink, blue, clear) on the finished goods. Outdoor exposure, indoor exposure in humid atmosphere, soil burial or contact, and electrical insulation compounds are typical areas where biocide addition is indicated. Since most commercial biocides are heavy metal derivatives, care must be taken to assess their effect on heat and light stability and compatibility with the vinyl system in which they are used. 

Bolger, J. C., New One Component Epoxy Insulation Compounds, Insulation, October 1969. 

Oparex 15 calcined calcium sulphate (Yesos Ibericos) was evaluated as a filler in plasticised PVC cable insulation compounds in comparison with two grades of calcium carbonate. Improvements were observed in tensile, electrical and low temperature properties, flammability and heat ageing characteristics and chemical resistance for calcium sulphate filled compounds, while no significant differences in water absorption and hydrolysis were noted. Studies of rheological properties showed improved processability in mixing and extrusion trials. URALITA... 

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