Flagged Polyester Filament

In the flagged polyester filament family, Flagged Polyester Filament is specified, supplied as base filament 0.15–0.60 mm with split flagged tips, drawn in round, triangular, cross-shaped, hollow, star-shaped and rectangular sections and set in straight rows, helical, staggered, zoned, wavy and random fill patterns.

Flagged Polyester Filament is used in custom cleaning brushes for fine dust pickup, wash brushes, coated panels, vehicle surfaces and delicate equipment.

It is usually weighed against Nylon PA, PBT and Polypropylene PP, and the deciding difference is moisture uptake and working temperature rather than anything you can read off the name.

Use a softer polymer or natural fiber for lower marking; use abrasive or metal wire for greater cutting action.

Flagged Polyester Filament is soft to medium; high tip density, which is why Flagged Polyester Filament changes contact through its filament or media size, free trim, density, profile, and engagement.

Filament-level figures for this grade and the ones it is usually compared to. A finished brush behaves differently again.

The part people get wrong: the same grade can feel soft or aggressive depending on diameter, trim and density. Specify that geometry before the material, or the sample will surprise you.

Flagged Polyester Filament takes up 0.1–1.0% (24 h; industry reference range).

Suitable for the wet or dry conditions stated in the application list; wash and dry retained-residue constructions after use.

What this means for your application: it barely absorbs water, so dry and wet contact pressure are effectively the same and the brush behaves alike on both duties.

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.

Temperature capability follows the polyester grade; flagging changes the filament tip geometry, not the base polymer service-temperature limit.

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.

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, 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.

Use the grade-specific chemical profile and confirm it against the actual chemical, temperature, exposure-time, and load conditions of your application.

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 Flagged Polyester Filament form, diameter or grade, trim, density, working temperature, cleaning fluid, and surface finish.

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.

Fine dust pickup, wash brushes, coated panels, vehicle surfaces and delicate equipment.

Where it turns up in practice:

• Laboratory Tube Cleaning
• CPAP Hose Cleaning
• Household Dish, Teapot & Kitchen Detail Cleaning
• Beverage Equipment Cleaning
• Food Equipment Cleaning
• Tube & Pipe Cleaning

It is normally set into these constructions:

• Custom Handheld Detail Brushes
• Custom Tube & Pipe Bore Brushes
• Custom Roller and Conveyor Brushes
• Custom Strip Seal Brushes
• Custom Floor Scrubber Sweeper Brushes

If the sample comes back rejected: Flagged tips load with sticky residue and are not used for aggressive cutting.

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 Flagged Polyester Filament without setting diameter, trim and density
• Using the material on a surface that cannot accept its contact level
• Ignoring temperature, liquid, motion or residue retention

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 13061-1; ASTM D143.

Source: Perlon — Synthetic Brush Filaments. Public manufacturer or material data supports the listed material form and service direction. Functional/profile labels do not replace grade-specific thermal data. Functional/profile labels do not replace grade-specific thermal data.