Class 105 polyvinyl acetal with self-bonding overcoat round copper magnet wire is widely used in audio and visual equipment (such as microphones, headphones, speakers, and hearing aids), micro vibration motors (including focusing motors, flat motors, and hollow cup motors), and electronic products (such as inductors, clock coils, coin mechanism coils, and buzzers).
Insulating Material
The conductor shall be coated with a dual film.
The underlying coating is based on a blend of polyvinyl acetal and phenolic resins . The superimposed coating is based on resins that are self-bonding in character.
NOTE—Polyvinyl acetal in this case refers to the condensation product of polyvinyl alcohol and an aldehyde and includes polyvinyl formal (Formvar).
Features:
Its insulation layer is made of polyamide resin and is coated with a self-adhesive layer. When heated or exposed to solvents, this enameled wire can bond together, forming self-fixing coils.
Table 1 Dimensions
| Insulation materials | Polyvinyl Acetal with self-bonding |
| Thermal Class | 105 |
| Dimensions | Type 1 and Type 2: 14-44 AWG; Type 3: 14-30 AWG |
| Standard | MW 19-C |
Table 2 Properties
| Adherence and flexibility | No cracks visible in the film coating |
| Minimum Percent Elongation | Not less than value in 25-38 |
| Heat shock | No cracks visible in the film coating after conditioning at 175ºC |
| Springback | Not greater than the value in Type1(mm): 42±0.127 ~ 66±0.127 Type2, type3(mm): 46±0.127 ~ 70±0.127 |
| Dielectric Breakdown | 14-23.5 AWG: type1: 2740V-3520V; type2: 4500V – 5690V; 24-37 AWG: type1: 1360V-2740V; ;type2: 2270V – 4870V; 38-56 AWG: 90V -1690V |
Table 3 Periodic conformance tests
| Dielectric breakdown rated temperature | Average not less than 75% of the value required at room temperature |
| Toluene / ethanol compatibility | No swelling or blistering in the film coating |
| Bond Strength At | No break in the coil specimen when subjected to the load specified in 18 AWG: 408 grams or 4.00 newtons 26 AWG: 76 grams or 0.75 newtons 36 AWG: No separation of turns other than the first or last turn |
| Thermoplastic flow | Median not less than 180°C |