Electrical properties

Electrical properties

Table 8 shows the general electrical properties of representative grades of TORAYCON™ PBT resin. Table 9 provides a comparison to other types of resins.
TORAYCON™ possesses favorable electrical properties—its superb resistance to heat and chemicals and low water-absorption make it the optimal resin for electrical and automotive components.

Table 8: Electrical properties of Toray's TORAYCON™ PBT resin
Property Unit ASTM 1401X06 1101G-30
Volume resistivity   Ω·m D257 4×1014 2.5×1014
dielectric breakdown strength   MV/m D149    
  Short duration, 1mm thickness     27 37
  Short duration, 3mm thickness     17 23
Dielectric tangent 50Hz   D150 3.3 3.7
  1kHz     3.3 3.7
  1MHz     3.3 3.6
Dielectric constant 50Hz   D150 0.002 0.002
  1kHz     0.002 0.002
  1MHz     0.02 0.02
Arc resistance   sec D495 144 120
Table 9: Comparison of electrical properties of plastics
  Volume resistivity
Dielectric constant
Dielectric tangent
Voltage resistance MV/m 1/8" thickness Arc resistance
TORAYCON™ 1401X06 4×1014 3.3 0.002-0.02 17 144
Polyacetal (copolymer) 1012 3.7 0.001-0.0015 20-23(1/16") Molten
Nylon 6 7×1012 3.4-4.0 0.01-0.03 23 140
Polycarbonate 2×1014 2.96-3.17 0.001-0.01 16 125
Modified PPO 1015 2.64-2.68 0.0007-0.0014 20-22 -
Diallyl phthalate 2×1014 3.4-3.6 0.009-0.011 18 118
Phenol resin 109-1010 5-15 0.08-0.50 12-13 20
Unsaturated polyester 1010-1012 3.2-4.3 0.006-0.05 20 125

Ⅰ. Volume resistivity

Figure 19: Temperature dependence of volume resistivity

Figure 19: Temperature dependence of volume resistivity

Figure 19 shows the temperature dependence of volume resistivity in the non-reinforced grade (1401X06). TORAYCON™ maintains favorable electrical insulating properties across a broad range of temperatures.
Table 10 shows the dielectric resistance of the glass-fiber reinforced grade (1101G-30) after causing thermal degradation. After 1,000 hours at 150°C, there is little change.

Table 10: Dielectric resistance of TORAYCON™ 1101G-30 after exposure to a high temperature for an extended duration of time
  Surface resistivity
Volume resistivity
Before 7 x1013 2 x1014
After 1,000 hours at 150°C 9 x1013 4 x1014

Measurement conditions: Voltage 100V, temperature 23°C, 50%RH

Ⅱ. Dielectric properties

Figures 20 and 21 show the temperature dependence of dielectric properties in the non-reinforced grade (1401X06). TORAYCON™ undergoes little change in dielectric properties across a broad range of temperatures. Also, as shown in Table 8, frequency has little effect either.

  • Figure 20: Temperature dependence of dielectric constant Figure 20: Temperature dependence of dielectric constant
  • Figure 21: Temperature dependence of dielectric tangent Figure 21: Temperature dependence of dielectric tangent

Ⅲ. Dielectric breakdown strength

TORAYCON™ non-reinforced grade (1401X06) exhibits favorable dielectric breakdown strength—17 MV/m at 3 mm thickness and 27 MV/m at 1 mm thickness.
The glass-fiber reinforced grade (1101G-30) does even better—23 MV/m at 3 mm thickness.
Both the 1401X06 and 1101G-30 grades maintain nearly all their dielectric breakdown strength even after two months of thermal degradation at 150°C.
According to Underwriters Laboratories, the heat-resistant temperature of the dielectric strength in TORAYCON™ 1401X06 and 1101G-30 grades is 140°C at thicknesses of 1/8 to 1/32 inch.

Ⅳ. Arc resistance

The generation of carbonized conducting paths on a resin surface resulting from arc discharge at high voltages is an important factor in the degradation of arc resistance. As shown in Table 8, the arc resistance of 1401X06 and 1101G-30 is 144 and 120 seconds, respectively—both superlative values for a thermoplastic resin.