Anti-Static and Conductive Brush Filament: Carbon Nylon & Fibre
Material guide · 7 min read · updated 2026-10-24
Ordinary nylon, PP and polyester filaments are electrical insulators. Brushing plastic film, paper, sheet or electronic parts with them can generate static charge instead of removing it. Anti-static and conductive filaments solve this by giving the charge a path to ground, or by ionising the air close to a charged surface.
The main options are carbon-loaded or carbon-coated nylon, carbon fibre, and fine metal wire. They differ in conductivity by many orders of magnitude, and the right choice depends on what you are protecting and whether the brush touches the product.
The ESD vocabulary in numbers
Static-control specifications usually use resistance classes defined by the ESD Association. In terms of volume resistivity, conductive materials are below 1 × 10⁴ Ω·cm, static-dissipative materials are from 1 × 10⁴ up to 1 × 10¹¹ Ω·cm, and insulative materials are 1 × 10¹¹ Ω·cm or higher. The equivalent surface-resistivity limits are 1 × 10⁵ and 1 × 10¹² Ω/sq. "Anti-static" is a looser marketing term covering conductive and some dissipative materials, so ask which class and test method a supplier means.
The main filament types
| Filament | Construction | Electrical data | Notes |
|---|---|---|---|
| Carbon-coated nylon 6.6 | About 1 µm conductive carbon layer on round PA66; 0.254, 0.41, 0.52 mm | About 6–10 × 10³ Ω per cm length; about 8 Ω·cm specific resistivity | Rated to about 110 °C; conductivity varies with humidity; coating wears at the same rate as the fibre |
| Anti-static (dissipative) nylon | Modified nylon (supplier-specific) | Charge decay 1.8 s vs 100 s for standard nylon (5 kV test, 21 °C, 29 % RH) | Dissipates charge faster but is not a true conductor |
| Carbon-black-blended nylon | Compounded fibre, e.g. 0.15 mm | Grounded through the handle or holder | Used in hand brushes for electronics assembly |
| Carbon fibre | Bundles of 7 µm filaments | 1.7 × 10⁻³ Ω·cm (standard-modulus fibre) | Very fine, very conductive; density 1.76 g/cm³ |
| Brass or stainless wire | Fine metal wire, e.g. 0.1 mm brass | Metallic conductor | Stiffer and heavier; can mark soft surfaces |
How anti-static brushes work
- Contact grounding: conductive bristles touch the charged surface and carry charge through the holder to an earthed frame. This needs a real ground connection. An ungrounded conductive brush simply holds the charge.
- Induction or ionisation: very fine conductive fibres such as carbon fibre, held close to a charged surface, ionise the air, and the ions neutralise the charge. Fine fibre diameter is what makes this work, which is why 7 µm carbon fibre is so common in static-eliminator strip brushes.
- Hand brushes for electronics often have a ground cord. One commercial design includes a 1 MΩ resistor in the cord to protect the operator.
- Strip brushes with carbon fibre or stainless wire in aluminium holders are the usual industrial format for film, paper, textile and plastic-bag lines. See strip brushes and brush seals.
Pros, cons and cautions
- Carbon fibre: extremely conductive and fine, so it works with light or no contact. It is brittle in bending, so it is not suited to scrubbing or heavy contact.
- Carbon-coated nylon: behaves mechanically like nylon and can clean while it discharges. Conductivity depends on humidity, and the temperature limit is low (about 110 °C).
- Dissipative nylon: gentlest on sensitive parts, but slower to discharge than true conductors.
- Metal wire: robust and fully conductive, but stiff, heavy and liable to scratch.
- Caution: one supplier warns that conductive fibres are not recommended near unencapsulated microcircuits, because shed fragments can cause short circuits. For direct contact with sensitive devices, the dissipative range is normally specified.
How to specify
State the job first: static elimination on a moving web, cleaning plus discharge on boards or parts, or grounding a rotating part. Then specify the filament (carbon fibre, carbon nylon, dissipative nylon or metal wire), the required ESD class or resistance and its test method, pile height, holder profile and length, and how the brush will be grounded. For strip formats, also give the holder dimensions. Our metal-channel strip brushes and flexible strip brushes list common profiles.
Ask the supplier to measure resistance on a finished sample from holder to bristle tip. Surface and volume resistance are normally measured to ANSI/ESD STM11.11 and STM11.12, and because carbon-coated nylon changes with humidity, the test humidity should be recorded. The filament rating alone does not prove the brush is grounded properly. Send line speed, web material and the brush-to-web distance with your RFQ.
Alternatives
Active ionising bars, which need a power supply, are an alternative for high-speed webs where a passive brush is not enough. For pure cleaning with no ESD requirement, standard PA66 or PA6 is cheaper. Where metal contact is acceptable, fine brass or stainless wire strip brushes give a robust conductive path.
Frequently asked questions
- What is the difference between conductive and anti-static brushes?
- Conductive brushes have resistivity below about 1 × 10⁴ Ω·cm and must be grounded to drain charge. Anti-static (dissipative) materials sit roughly between 1 × 10⁴ and 1 × 10¹¹ Ω·cm and drain charge more slowly, which is gentler on sensitive electronics.
- Do carbon fibre anti-static brushes need to touch the surface?
- Not always. Very fine carbon fibres held close to a charged surface ionise the air and neutralise the charge. The brush must still be properly grounded.
- Does an anti-static brush need to be grounded?
- Yes, for conductive and carbon-fibre brushes. Without a path to earth the charge has nowhere to go. Hand brushes often use a ground cord with a current-limiting resistor.
- Is conductive nylon affected by humidity?
- Yes. Supplier data for carbon-coated nylon 6.6 notes that conductivity changes with humidity. Specify and test it under your actual working conditions.
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