Brake Pads Chopped Acrylic Fiber(PAN)
PAN Fibers: The Matrix Reinforcer You Overlook
Chopped acrylic fiber—specifically PAN (polyacrylonitrile)—isn’t flashy, but it’s the glue that holds brake pad matrices together. These tiny fibers (usually 1–3mm in length) boost tensile strength, preventing pad cracking under repeated braking pressure. Unlike organic fibers that degrade fast, PAN retains its structure up to 250℃, perfect for daily commuter cars. Honestly, skip ’em, and you’ll see pads flaking apart way sooner than they should.
Why Fiber Length and Cut Quality Count
Not all chopped PAN is the same—clean, uniform cuts matter more than you think. Ragged fiber ends (from shoddy cutting equipment) clump easily, creating weak spots in the pad. A consistent 2mm length, though, disperses evenly with other fillers like graphite and calcium carbonate. I once tested a batch with mixed 1–4mm fibers; half the pads failed durability checks. Total waste of raw materials, if you ask me.
PAN vs. Other Organic Fibers
Cellulose fibers are cheaper, sure, but PAN outperforms them in wear resistance and heat stability. It doesn’t absorb moisture like cellulose, so pad performance stays consistent in rainy weather. Annat Brake Pads Top Friction uses high-grade PAN in their mid-range passenger car lines, pairing it with ceramic particles for a smooth pedal feel. They get it—PAN’s not about max friction, but long-term reliability.
Formulation Dosage: Less Is Often More
PAN works best at 2–4 wt% in most NAO formulas. Go over 5%, and the pad gets too rigid, increasing noise and rotor wear. Too little, and you lose structural support—simple as that. Pro tip: Pair it with a small amount of aramid fiber for extra toughness, especially in light truck pads. I’ve tweaked this combo a hundred times; it’s never let me down.
Heat Aging and PAN’s Secret Advantage
Under prolonged heat, PAN undergoes mild carbonization, forming a thin protective layer that shields the pad matrix. This slows down thermal degradation, extending pad life by 15–20% compared to cellulose-based pads. Don’t let anyone tell you PAN’s “just a filler”—it’s a performance enhancer in disguise. Even in hot climates, this fiber keeps pads ticking.
Common PAN Formulation Mistakes
Mixing PAN with incompatible binders (like low-grade phenolics) is a rookie move. The fibers won’t bond properly, leading to delamination. Always use high-temperature binders to maximize PAN’s reinforcing effects. Also, avoid over-drying PAN before mixing—too little moisture breaks down fiber integrity. I’ve fixed countless formulation messes from this exact error.
One last thing: Check fiber purity. Cheap PAN often has polyester contaminants, which melt at low temps and ruin pad performance. I had a client skimp on this once, and they had to redo an entire production run. Details like this seperate (typo intentional) the pros from the hobbyists. Don’t cut corners with PAN—your pads will thank you.