PA6 Nylon

PA6 Nylon belongs to the polyamide filament group, supplied as filament and brush fill, drawn in round, triangular, cross-shaped, hollow, star-shaped, hexagonal and rectangular sections and set in straight rows, helical, staggered, zoned, wavy and random fill patterns.

PA6 Nylon is used in custom cleaning brushes for economical industrial scrubbing, tube cleaning and strip-brush contact in moderate wet or dry service.

The realistic alternatives are PA66 Nylon, Polypropylene PP and PBT. What separates them here is moisture uptake and working temperature, not headline strength.

Compare PA6 Nylon with PA66, PP, PBT. Change material when wet stiffness, temperature, chemical resistance, conductivity, particle shedding, or surface marking becomes the limiting factor.

PA6 Nylon is medium; Shore D about 75-82; filament stiffness increases with larger diameter and shorter trim height, and PA6 Nylon changes brush stiffness through filament diameter, free trim, density, crimp, and contact. Use finer filament and longer trim for conformable contact; use coarser filament, shorter trim, or higher density for stronger displacement or cutting.

Published ranges for the filament itself. Read them as a shortlist tool, not as brush performance.

The part people get wrong: stiffness is not a property of the material on its own. A 0.50 mm filament on a 15 mm trim is stiffer than a 0.30 mm filament on a 25 mm trim in the same grade. Fix diameter and trim first, then confirm the material.

PA6 Nylon takes up 1.5–3.0% (24h, ISO 62/ASTM D570), rising to 8–10% at saturation, which is the figure that matters for anything left submerged.

PA6 and PA66 absorb moisture; PA610, PA612 and PA12 retain stiffness better in wet service; this moisture response matters in economical industrial scrubbing, tube cleaning and strip-brush contact in moderate wet or dry service.

What this means for your application: the filament grows and softens as it takes on water, and tip pressure goes with it. The reach you measured dry is not the reach you get wet.

A practical check: soak a sample for an hour and re-measure the trim. If it has moved enough to change the contact band, the grade is wrong for the duty.

Maximum continuous use: 93°C; maximum short-term use: 121°C.

Design to that answer rather than to a raw-material datasheet figure: a brush rating already accounts for filament working under load rather than raw polymer sitting in an oven.

Published melting point is 215–225°C. That is a material property, not an operating ceiling, and using it to justify a hot wash is the fastest way to ruin a brush.

Where it stops working: validate with a sample if the process sits near the top of that band. If the filament takes a permanent set under load, step up to PBT or PA66 Nylon, which hold a higher continuous temperature.

The usable limit also moves with diameter, trim and contact pressure. A fine filament under light load tolerates more than a thick one under heavy scrubbing.

It stands up to water, oils, mild detergents and dilute alkalis.

What degrades it: strong mineral acids, phenols and strong oxidizers.

The same cleaner can be harmless or destructive depending on how strong it is, how hot it runs and how long it sits. Quote the concentration and the dwell time, not just the product name.

Before you commit to a quantity: Specify the exact PA6 Nylon grade or alloy, filament or profile size, color, straight or crimped form, working temperature, wet or dry use, chemical exposure, surface finish, and any required material documentation.

About 0.05 mm. Below that the filament turns fragile and breaks under ordinary contact pressure, so 0.05–3.00 mm is the working range.

Free trim runs 3–300 mm, and the two interact: a finer filament needs a shorter trim to keep useful stiffness, while a thicker one carries a longer trim and still lands pressure on the tip.

Split the range by duty: roughly 0.05–0.79 mm for light wiping, dusting and surfaces that mark easily, and 0.79–3.00 mm where residue is packed on and point pressure matters more than surface risk.

Tip treatments available on this filament: end rounding, tapered-tip grinding, silicone-oil coating, anti-static coating and antibacterial coating.

In practical brush terms: reaching deep into a bore or crevice is a diameter problem before it is a length problem. A thicker filament on a moderate trim pushes further in before the tips fold over.

Economical industrial scrubbing, tube cleaning and strip-brush contact in moderate wet or dry service.

The applications that keep coming back to this grade:

• Laboratory Tube Cleaning
• CPAP Hose Cleaning
• Dental Tool Cleaning
• Industrial Machine Cleaning
• Dust Removal
• Medical Instrument Cleaning

The constructions that usually carry it:

• Custom Tube & Pipe Bore Brushes
• Custom Roller and Conveyor Brushes
• Custom Handheld Detail Brushes

If the sample comes back rejected: PA6 takes up more moisture than long-chain nylons, which can reduce stiffness and dimensional stability in continuously wet service.

A usable specification carries the construction, the filament diameter and free trim, the density and contact setting, and the service conditions: wet or dry, temperature, and what the cleaner actually is.

The mistakes that most often send a sample back:

• Selecting PA6 Nylon from the material name alone without setting filament diameter, trim length, and density
• Using dry stiffness to predict wet behavior without checking moisture absorption or liquid exposure
• Ignoring trapped abrasive particles, chemical concentration, temperature, or contact motion when assessing surface risk

Reference standards behind the figures on this page: ISO 527-1:2019; ASTM D638; ISO 62:2008; ASTM D570-22; ISO 868:2003; ASTM D2240-15(2021); ISO 4892-3:2024; ASTM G154-23; UL 94.

Source: American Brush Manufacturers Association — Brush Lingo — Nylon 6. ABMA brush-filament guidance; confirm the actual supplied grade if the project runs near the limit.