What is the anti-static performance of the rubber disc?

1. External anti-static coating (spray/immersion, low-cost temporary)
Principle: Ordinary PS/ABS adhesive discs are sprayed with anti-static liquid on the surface to form a conductive film on the surface
Performance: Short term failure of 3-6 months, coating detachment in friction, collision, high temperature, and dry environments, resistance surge back to insulation; Humidity<40%, anti-static quickly deteriorates, relying on moisture in the air for conductivity
Cost: Cheap, mostly used for one-time export of ordinary small items (resistors, capacitors, LEDs)
Disadvantages: After the edge and axis wear, there is no ESD in some areas, which makes it easy for static electricity to penetrate the chip
2. Add permanent anti-static measures to the raw materials (carbon black/carbon fiber mixed particle injection molding, long-lasting)
Principle: During granulation, carbon black and conductive carbon fiber are mixed into PS/ABS/PC raw materials, forming a complete conductive network without surface coating
Performance: Permanent anti-static for 3-5 years, wear-resistant, resistant to high and low temperatures, with small resistance fluctuations due to temperature and humidity changes; Polish and knock off the surface, but the interior still has anti-static performance
Divided into two categories:
① Carbon black PS black disk: 10 ⁶~10 ⁹ Ω, the most cost-effective, regular IC bulk shipment
② Carbon fiber ABS/PC: 10 ⁵~10 ⁷ Ω, with more stable resistance and good toughness, suitable for repeated use of precision components in automotive and military applications
Cost 25%~40% higher than external coating
The substrate material affects the anti-static stability
HIPS/PS adhesive disc (most commonly used)
Internally added carbon black: stable resistance value of 10 ⁷~10 ⁹, stable at room temperature; High temperature>75 ℃ is prone to resistance drift and not suitable for high-temperature SMT workshops
External coating: The low temperature is acceptable, but it will fail in the high temperature workshop for 1-3 months
ABS rubber disc (cyclic turnover)
Modified carbon fiber ABS: resistant to temperatures of 95-110 ℃, with minimal resistance fluctuations in high and low temperature environments. Long term ESD discs are preferred for automotive components
PC rubber disc (high-end)
Carbon black modified PC: temperature resistance of 120 ℃+, anti-static stability throughout the year, transparent/black optional, BGA、 Crystal oscillator specific