Recording magnetic tapes

Magnetic recording tape, in addition to using plastic films as a support for the recording... 

A typical polyester molecule has 50 to 100 repeat units and a molar mass between 10,000 and 20,000 g/mol. PET can be formed into fibers (such as Dacron) or films (such as Mylar). Mylar films, which can be rolled into sheets 30 times thinner than a human hair, are used to make magnetic recording tape and packaging for frozen food. Dacron is best known for its use in clothing, but it has many other applications. For example, tubes of Dacron are used as synthetic blood vessels in heart bypass operations because Dacron is inert, nonallergenic, and noninflammatory. 

Because flexible films have excellent strength and good electrical and thermal properties, have low permeability to gases, water, oil, odour and could be sterilised so they are used in capacitors, cables, magnetic recording tapes, typewriter ribbons, food packaging, tracing film, book covers, etc. The film is coated with aluminium by vacuum disposition and used for decoration and in textiles. 

Fibers—garments, permanent press and wash wear garments, felts, tire cord film—magnetic recording tape, high-grade film... 

Chemically, Dacron and Mylar are polymers made from a ring structure called dimethyl terephthalate and ethylene glycol (HO-CH2CH2-OH). The polymer unit is called polyethylene terephthalate, or PET. Dacron fiber is used in tires and fabrics, and is even used to repair blood vessels. Mylar is used in magnetic recording tape. In the 1960s, it was used in huge balloons that were sent into orbit around Earth. Plastic soda containers are made of PET. 

Phenanthroline and some of its alkyl-substituted derivatives improve the heat stability of polyesters594 and magnetic recording tape.595 They also improve the color of cured polyester resins.596 They are also useful in various electroplating and electrolytic processes597-601... 

Cladding for optical fibers Coating for magnetic recording tape Coatings for textiles and leather Housings for office machines... 

Like amides, esters are common both in nature and in the chemical industry. Animal fats and vegetable oils are mixtures of esters, as are waxy materials such as beeswax and spermaceti. Plants often synthesize esters that give the characteristic tastes and odors to their fruits and flowers. In addition to making synthetic esters for flavors, odors, and lubricants, chemists have made synthetic polyesters such as Dacron polyester fiber used in clothing and Mylar polyester film used in magnetic recording tapes. 

Dacron fiber is used to make fabric and tire cord, and Mylar film is used to make magnetic recording tape. Mylar film is strong, flexible, and resistant to ultraviolet degradation. Aluminized Mylar was used to make the Echo satellites, huge balloons that were put into orbit around the Earth as giant reflectors in the early 1960s. Polyethylene terephthalate) is also blow-molded to make plastic soft-drink bottles that are sold by the billions each year. 

Cladding for optical fibers Coating for magnetic recording tape Coatings for textiles and leather Housings for office machines Source Brady, R. F., Jr. in Modem Fluoropolymers (Scheirs, J., Ed.), John Wiley Sons, New York, p. 130, 1997 (With permission). 

Use Magnetic recording tape, drafting and engineering reproduction materials, metallic yarn, roll leaf, pressure-sensitive tapes, packaging, dielectric material in capacitors, wire and cable, motors, generators, transformers, and oils. 

Chromium(IV) oxide, Cr02, is usually made by controlled decomposition of Cr03. It is a brown-black solid which has the rutile structure and is a metallic conductor (compare with VO2). It is ferromagnetic and is widely used in magnetic recording tapes. 

The rheological and wetting properties of dispersions are ol prime importance in the coating not only of photographic film but also of paper products and magnetic recording tape. 

The fabrication of magnetic recording tapes and discs is relatively simple a suspension of the magnetic particles is deposited on the plastic substrate, under an aligning magnetic field. The solvent is evaporated a dry binder remains to keep the particles strongly attached to the substrate. The tape is finally rolled to obtain a compact coating. 

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