Diphenyl resins.
A series of products known as Aroclors and made by chlorinating diphenyl are available in commercial quantities.
Diphenyl was commercially produced for the first time by Swann Research, Inc., at Anniston, Ala., about 1928. The demand for it as a heat-transfer medium resulted in large scale output. Later it was found that certain of the chlorinated compounds of diphenyl possess valuable resin properties.
The Aroclors range from a clear mobile oily liquid to an amber colored transparent solid. They are thermoplastic, do not polymerize or oxidize, and are therefore nondrying. They may be dissolved in varnish oils, such as tung oil and linseed oil, to give varnishes which are resistant to alkali and water. The diphenyl resins are good adhesives on metal and glass and give strong joints between such surfaces. They have a high dielectric constant, resistivity, and a low power factor. Their chief use is in wire insulation.
The domestic production of chlorinated diphenyls is, at present, solely by the Monsanto Chemical Company, St. Louis, Mo.