Compact disc manufacture

E.A. LeMaster, Compact Disc Manufacturing http //www.ee.washington.edu/ conselec/W94/edward/edward.htm, (1994). 

GaAs, GaAlAs, and GaP based laser diodes are manufactured using the LPE, MOCVD, and molecular beam epitaxy (MBE) technologies (51). The short wavelength devices are used for compact disc (CD) players, whereas the long wavelength devices, mostly processed by MBE, are used in the communication field and in quantum well stmctures. 

The functional groups that typically participate in this type of polymerization are carboxyl, amine, and alcohol groups. Examples of step growth polymers include polyesters and nylons, which are often spun into fibers used to manufacture carpeting and fabrics, and polycarbonates, which are converted into compact discs, jewel cases, and the large bottles used in water coolers. 

The major uses of BPA are in the production of polycarbonate resins (63%) and epoxy resins (27%). Polycarbonates have major outlets in automotive parts, compact discs, eyeglasses, and sheet and glazing applications, and have caused bisphenol A consumption to more than double during the past decade. Epoxy resins are two-component adhesives for very strong bonding. Miscellaneous uses include flame retardants (mostly tetrabromobisphenol A) and other polymer manufacture. Polycarbonate grade bisphenol A is >99% p,p isomer. The epoxy grade is 95% p,p. The p,p and o,p isomers can be separated by a combination of distillation and crystallization. 

Organic polymers are manufactured and used on a massive scale as plastics and elastomers, films and fibres in areas as diverse as clothing, car tyres, compact discs, packaging materials, prostheses and most recently electroluminescent and electronic devices and sensors. The enormous growth in the use of organic polymeric materials since the 1930s can be mainly attributed to their ease of preparation, lightweight nature and unique ease of fabrication. 

Spin coating utilizes centrifugal forces created by a spinning substrate to spread a liquid evenly over its surface. Current applications are in photoresist technology for the microelectronic industry and in the manufacture of protective overcoats and adhesives for the optical storage industry (compact discs and DVDs).5... 

Radiation curing is an important part in the manufacture of compact discs and digital versatile disks (DVDs). In the production of compact disks the replication and formation of the protective coat can be carried out with the use of UV curing.59 The coatings are commonly based on methacrylates. 

In addition to the construction industry, phenol has many other applications. It is used in pharmaceuticals, in herbicides and pesticides, and as a germicide in paints. It can be used to produce caprolactam, which is the monomer used in the production of nylon 6. Another important industrial compound produced from phenol is bisphenol A, which is made from phenol and acetone. Bisphenol A is used in the manufacture of polycarbonate resins. Polycarbonate resins are manufactured into structural parts used in the manufacture of various products such as automobile parts, electrical products, and consumer appliances. Items such as compact discs, reading glasses, sunglasses, and water bottles are made from polycarbonates. 

Another difference between magnetic media and CD-ROM drives is that CD-ROM drives are read-only devices (CD-ROM stands for Compact Disc-Read-Only Memory). The only way of writing to a CD-ROM is during manufacture time, where the pits are burned into the substrate of the disc. Once written, they cannot be erased. 

Nicad batteries are used in a large variety of appliances, including compact disc players, cell phones, pocket recorders, handheld power tools, cordless telephones, laptop computers, camcorders, and scanner radios. A few automobile manufacturers have explored the possibility of using nicad batteries in electric cars. For example, the Mitsubishi Corporation of Japan built and marketed an experimental car called the Libro EV that operated on either traditional lead batteries or on nicad batteries. 

Nickel is also very popular in the manufacture of batteries. Nickel-cadmium (nicad) and nickel-metal hydride (NiMH) batteries are the most popular of these batteries. They are used in a great variety of appliances and electronics, including hand-held power tools, compact disc (CD)... 

The sound from your new compact disc (CD) is so clear and crisp that it seems as if the musicians are in the same room. The clarity of the sound is possible thanks to the chemical process of metallic depositing and electroplating used in the manufacturing of CDs. 

Polyesters with two ester groups bonded to the same carbon are known as polycarbonates. Lexan is produced by the reaction of phosgene with bisphenol A. Lexan is a strong, transparent polymer used for bulletproof windows and traffic-light lenses. In recent years, polycarbonates have become important polymers in the automobile industry as well as in the manufacture of compact discs. 

Sharpless, G., CD and DVD disc manufacturing, on www.disctronics.com, 2003. Wimberger-Friedl, R., Analysis of the Birefringence Distributions in Compact Discs, Polym. Eng. ScL, 30, 813, 1990. 

Phosgene is a highly toxic gas that has been used as a chemical weapon at times in the past. It is now used in the manufacture of polycarbonates, which are used to make compact discs and plastic eyeglass lenses. Phosgene is produced by the reaction, CO + CI2 — COCI2. Given an excess of carbon monoxide, what mass of chlorine gas must be reacted to form... 

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