Insulating paper

In the manufacture of a laminate for electrical insulation, paper, which is the best dielectric, is normally selected as the base reinforcement. An electrical grade of paper is in fact a better dielectric than the resin and thus in eonditions... 

Property Unit Paper for h.t. insulation Paper for it. insulation Fine fabric Asbestos felt Glass fabric... 

See also PEROXIDISABLE COMPOUNDS, INSULATION, PAPER TOWELS... 

The nonahydrate and other hydrated aluminum nitrates have many apph-cations. These salts are used to produce alumina for preparation of insulating papers, in cathode tube heating elements, and on transformer core laminates. The hydrated salts are also used for extraction of actinide elements. 

Lead hydroxide is used in making porous glass in electrical-insulating paper in electrolytes in sealed nickel-cadmium batteries in recovery of uranium from seawater and as a catalyst for oxidation of cyclododecanol. 

Aluminum nitrate is used in antiperspirants, for tanning leather, as a corrosion inhibitor, in the preparation of insulating papers, on transformer core laminates, in incandescent filaments, and in cathode ray tube heating elements (HSDB 1995). 

Highly cyanoethylated celluloses with a DS of about 2.5 are soluble in polar organic solvents. Because of an unusually high dielectric constant and low dissipation factor they can be used as the resin matrix for the phosphorous and electroluminescent lamps. Cyanoethylated kraft wood pulp with a DS of only about 0.2 is used for making insulation paper for transformers. Cyanoethylated paper has also a good thermal and dimensional stability. 

U, S. Army used double-base powder for small arms. Linde introduced Oxyliquit, the first explosive of liquid-oxygen type, prepared from charcoal saturated with liquid air and enclosed in an insulating paper wrapper. 

The paper and textile industries have been concerned about the aging, deterioration, and degradation of cellulosic materials at elevated temperatures for practical reasons, such as the performance of tire yarn and electrical insulation paper, and the problems involved in drying or processing the cellulosic materials in general. However, due to the practical nature of these problems, the reactions involved have often been measured in terms of loss of strength and other physical properties. 

Formaldehyde (CH2O) release was measured for seven types of consumer products pressed wood, urea formaldehyde foam materials, clothes, insulation, paper, fabric, and carpet. A modified Japanese Industrial Standard (JIS) desiccator test was used to measure release rate coefficients and to rank 53 products. Ten pressed wood products and five urea formaldehyde foam products showed the highest CH2O releases (1-34 mg m 2.day"b The remainder, representing all product types, had lower releases ranging from 680 yg m 2.day to nondetectable levels. In other studies, CH2O release was measured in a ventilated chamber for single samples of particle board, plywood, insulation, and carpet. 

The content of particulate PAHs can be measured with an instrument originally developed at ETH in Zurich (Burtscher et al., 1982). In this instrument, small soot particles that have accumulated a deposit of PAHs from combustion processes are selectively photo-ionized by UV light. After the electrons have been removed, positive ions are collected on an insulated paper filter, and the current from the charged paper filter is measured by means of a sensitive electrometer. The instrument can be calibrated against a PAH mixture, for example, one representative of vehicle exhaust, using the result from a gas chromatograph as reference. The instrument operates within the concentration range 1-2000 ngW. 

Anhydrous aluminum nitrate [13473-90-0] is covalent in character, easily volatilized, and decomposes on heating (22). Hydrated aluminum nitrate is used in the preparation of insulating papers, on transformer cote laminates, and in cathode-ray tube heating elements. Solution of aluminum hydroxide through digestion of cote materials in nitric acid has been proposed in aluminum extractive metaUuigy. The resulting solution of aluminum nitrate is separated from other metal ions, and the aluminum oxide is recovered by thermal decomposition of the aluminum nitrate solution (23,24). 

Aramid pulp is widely used as a substitute for asbestos. The aramid paper is used as insulating paper. In this case, mica, ground quartz, glass fibers, alumina, or talc, can be incorporated to improve the insulating properties. In contrast, if alumina laminae, carbon black, or stainless steel short fibers are incorporated, electrical conductive papers are obtained. Aramid paper is also used as a reinforcing agent in honeycombs. 

For the effect of cation of metal salt of polymer complex, it was observed that [Figs. 7.7b and 7.8b], CMC-Zn[H] complex provided paper sheet with greater dielectric properties than that produced by CMC-Fe[IH] complex. Both type of complexes produced relatively high insulating paper than paper made from untreated wood pulp. The results obtained are probably due to the change of the type of combination between metal and cellulose. However, in case of Zn[H], the ionical bond is formed, while chelated covalent coordinated bond is formed in case of Fe[IH] [47]. 

From the above results, it could be concluded that the addition of polymer complexes to wood pulp during beating process was successful for producing new insulating paper sheet with high strength properties. This surprising data persuaded us to... 

CAS 1343-98-2 EINECS/ELINCS 215-683-2 Uses Thickener for cosmetics, pharmaceuticals, elec., insulation, paper, film, pesticides, plastics industries carrier, grinding aid, suspending agenL flow aid in pesticides thickener and thixotrope in filled polyester gel coats, laminating resins antiblock in PE and PP blown films flow aid for hygroscopic materials with poor flow chars., e.g., vitamins inert carrier for actives... 

An aramid insulating paper with enhanced strength, smoothness, and uniformity can be prepared by [47] ... 

Calendering the dried paper sheets at a high temperature to obtain the desired aramid insulating paper. 

Katayama J, Ohki Y. Comparisons of partial discharge resistance and dielectric properties after water absorption between polyetherimide and aramid insulating papers. lEEJ Trans Fundam Mater 2013 133(2) 51-6. 

The arrangement of the windings of the PT is shown in Fig. 4.3.2.2. Each different sections of the primary winding is made of 31 AWG wire, whose capacity for maximum current is 0.160 A, with a resistance of 435 Q / km. Each section consists of 55 layers and 200 turns per layer so that it has an electrical gradient of about 130 V per layer. Between each layer exists one or two layers of insulating paper impregnated with varnish. It has 3 metal screens (brass) placed in different areas, which are not only used to obtain a uniform distribution of the electric field inside the PT, but also serve as a connection between the different windings. 

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