PA66 Nylon

PA66 Nylon sits in the polyamide filament family, supplied as filament, roller and strip 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.

PA66 Nylon is used in custom cleaning brushes for firm industrial rollers, floor scrubbers and strip brushes that need strong bend recovery and wear resistance.

Where a project stalls on material choice, the comparison is normally against PA6 Nylon, PBT and PET Polyester, and it turns on moisture uptake and working temperature.

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

PA66 Nylon is medium-firm to firm; Shore D about 80-85; generally stiffer and better recovery than PA6 at similar filament diameter; PA66 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.

The published filament ranges, set against the grades it competes with. These are filament figures, not finished-brush values.

The part people get wrong: the number that decides scrubbing pressure is diameter over trim length, not the grade name. Two brushes in this material can behave nothing alike.

PA66 Nylon takes up 1.0–1.8% (24h, ISO 62/ASTM D570), rising to 7–9% 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 firm industrial rollers, floor scrubbers and strip brushes that need strong bend recovery and wear resistance.

What this means for your application: water changes the working diameter and the spring rate together, so wet performance has to be checked rather than assumed from a dry trial.

A practical check: run one wet cycle and compare tip contact against the dry state. If the wet brush leaves residue behind or no longer reaches the bottom of the bore, change the material rather than the geometry.

Maximum continuous use: 120°C; maximum short-term use: 180°C.

The filament tables quote 100–120°C continuous and 150–180°C peak. The tighter number above is the one to build to, because a brush is loaded while it is hot.

The melting point of 255–265°C is not a service limit and should never be used to set a wash temperature. It is the point at which the filament stops being a solid at all.

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 PET Polyester or PBT, which hold a higher continuous temperature.

Diameter, trim length and applied load all shift the real limit, so a thin filament touching lightly survives conditions that would flatten a thick one under pressure.

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

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

Compatibility is a function of concentration, temperature and contact time together. A short rinse in a dilute solution is a different exposure from an overnight soak in a concentrated one, even with the same chemical on the label.

Before you commit to a quantity: Specify the exact PA66 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.

The floor is roughly 0.03 mm; finer than that and the filament snaps rather than flexes. In practice you are choosing inside 0.03–3.00 mm.

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 0.03–0.77 mm for light wiping, dusting and surfaces that mark easily, and 0.77–3.00 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, chemical etching, silicone-oil coating, ptfe 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.

Firm industrial rollers, floor scrubbers and strip brushes that need strong bend recovery and wear resistance.

The cleaning work it is specified for most often:

• Industrial Machine Cleaning
• Screen & Sieve Cleaning
• Floor Scrubbing
• Dust Removal
• Brick, Tile & Building Material Machine Brush Use
• Pipe Robot Brush Attachment Use

Brush types built with this fill:

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

If the sample comes back rejected: For food, medical or chemical service, use a named PA66 grade with the documentation and exposure data required by the project.

Send the brush type, filament diameter, free trim length, density, contact setting, wet or dry duty, working temperature and the actual cleaning chemistry together. Any one of them on its own leaves the stiffness undefined.

What usually goes wrong at this step:

• Selecting PA66 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; ISO 37; ASTM D412; ISO 48-4.

Source: American Brush Manufacturers Association — Brush Lingo — Nylon 6.6. ABMA brush-filament guidance; confirm the actual supplied grade if the project runs near the limit.