Electrically heated device employing conductive-crystalline polymers
Abstract
Abstract A hair curler employing a heater element formed of a conductive crystalline polymer is disclosed. The polymer, loaded with conductive particles, such as carbon black, has a positive temperature coefficient (PTC) of resistivity characteristic and combines a fast warm-up time with a slow cool down time due to the phase change of amorphous polymer to crystalline polymer upon cooling. The heat of fusion curve of the crystalline polymer is related to the temperature versus resistivity curve such that a sharp rise in resistance above an anomaly temperature and in and around the operating temperature of the curler limits the heat generation and prevents some of the crystalline polymer from changing state and maintains the structural integrity of the polymer. Since the polymer retains its shape, no special sealing means is required to confine it as in fusible wax devices. Means are disclosed to make electrical contact to the heater element and for mounting it within an outer hair curler shell.
Inventors
- 👤 John V Meyer
Bibliographic Details
Claims Analysis
Total Claims: 9References Cited (Backward Citations)
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