An improved process for heating compositions by high-frequency alternating electric currents

Abstract

Abstract Process for the heat treatment of synthetic thermoplastic and thermosetting resins, particularly polyvinyl chloride, comprises heating at a predetermined temperature by the action of a high-frequency alternating electric current a composition containing the resin mixed with organic polar material which is molten at said temperature and which comprises an organic compound having a dipole moment in excess of one Debye unit. The organic polar material may be a single compound, e.g. a -nitronaphthalene, p-nitraniline, m-nitraniline, p-nitrophenol, or m-dinitrobenzene or a mixture, preferably eutectic, of organic compounds at least one of which has a dipole moment in excess of one Debye unit, e.g. m - dinitrobenzene and m-nitraniline, p-nitraniline and phenol, a -nitronaphthalene and naphthalene, a -nitronaphthalene and 2-nitro-4-hydroxytoluene, a -nitronaphthalene and benzophenone, a -nitronaphthalene and p-nitraniline, or may be a commercial mixture of dimethylol nitroethanes. Lead stearate and plasticiser may be added.ALSO:Process for the heat treatment of natural or synthetic rubber comprises heating at a predetermined temperature by the action of a high frequency alternating electric current a composition containing rubber mixed with organic polar material which is molten at the said temperature and which comprises an organic compound having a dipole moment in excess of one Debye unit. The organic polar material may be a single compound, e.g. a -nitro naphthalene, p-nitraniline, m-nitraniline, p-nitrophenol, or m-dinitrobenzene or a mixture, preferably eutectic, of organic compounds at least one of which has a dipole moment in excess of one Debye unit, e.g. m-dinitrobenzene and m-nitraniline, p-nitraniline and phenol, a -nitronaphthalene and naphthalene, a -nitronaphthalene and 2-nitro-4-hydroxytoluene, a -nitronaphthalene and benzophenone, a -nitronaphthalene and p-nitraniline, or may be a commercial mixture of dimethylol nitroethanes. The process may be used for uniting two vulcanized rubber surfaces by coating one or both of the surfaces with a heat vulcanizable rubber composition according to the invention, pressing the surfaces together and subjecting the assembly to a high frequency alternating electric current, or for repairing a damaged rubber tyre by filling a cavity in the damaged portion with a rubber composition according to the invention and heating by a high frequency alternating electric current.

Inventors

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