Acrylic (PAN / 腈纶 / "Synthetic Wool")
Acrylic is polyacrylonitrile (PAN) fiber — a synthetic made from at least 85% acrylonitrile monomer plus comonomers for dyeability and processability, spun via dry or wet spinning. Its defining trait is a soft, wool-like hand combined with the best sunlight and weather resistance of any fiber, natural or synthetic. This makes it the dominant fiber for outdoor textiles, awnings, and knitwear where wool-like aesthetics are desired at lower cost. Global production is approximately 2 million tons/year, with China (~0.8 Mt) as the second-largest producer.
Quick Facts
| Type | Synthetic (addition polymer); at least 85% acrylonitrile (CH₂=CH–CN) + comonomers |
| Spinning method | Dry spinning (DMF solvent) or wet spinning (NaSCN or HNO₃ solvent); cannot be melt-spun (degrades below melting point) |
| Commercialized | 1953 (DuPont: Orlon®); Bayer: Dralon® |
| Global production | ~1.8–2.0 million tons/year; China ~0.8 Mt; declining due to competition from polyester |
| Density | 1.14–1.19 g/cm³ (lightweight; similar to nylon) |
| Moisture regain | 1.2–2.0% (low; slightly better than polyester's 0.4%) |
| Thermal behavior | No distinct melting point; softens ~190–230°C; decomposes ~250°C; flammable (LOI ~18%) |
| Key trade names | Orlon® (DuPont), Dralon® (Bayer), Cashmilon®, Acrilan®, Dolan® |
Properties
| Property | Rating | Engineering implication |
|---|---|---|
| Sunlight / UV resistance | ★★★★★ Best of all fibers | Outperforms every natural and synthetic fiber; the defining acrylic advantage; outdoor textiles, awnings, boat covers |
| Hand feel | ★★★★★ Wool-like | Soft, warm, bulky — the reason it's called "synthetic wool"; dominant in knitwear and sweaters |
| Bulk / loft | ★★★★★ Excellent | High-bulk acrylic (膨体纱) produced by blending high-shrink + low-shrink fibers → differential shrinkage in steaming → bulky yarn |
| Strength | ★★☆☆☆ Low (2.0–3.0 cN/dtex) | Weaker than polyester and nylon; adequate for knitwear, insufficient for industrial uses |
| Elastic recovery | ★★★☆☆ Moderate | Better than cellulosics; below wool and nylon; adequate for knitwear shape retention |
| Moisture regain | ★★☆☆☆ Low (1.2–2%) | Better than polyester but still hydrophobic; static-prone; often blended with hydrophilic fibers |
| Abrasion resistance | ★★☆☆☆ Poor | Below polyester and nylon; prone to pilling (high-bulk structure + moderate strength) |
| Chemical resistance | ★★☆☆☆ Poor | Sensitive to acids and alkalis; the cyano group (–CN) is chemically reactive; worse than polyester and nylon |
| Flammability | ★☆☆☆☆ Highly flammable | LOI ~18% (lower than cotton at ~18%); burns readily; not self-extinguishing; FR variants available |
Advantages vs. Limitations
Advantages
- Best sunlight and weather resistance of all textile fibers
- Soft, warm, wool-like hand at lower cost than wool
- Excellent bulk and loft (膨体纱 / high-bulk yarn technology unique to acrylic)
- Lightweight (density ~1.17)
- Good color fastness; can be gel-dyed for exceptional brightness
- Resistant to mildew, insects, and microorganisms
- Quick-drying
- Can be engineered as carbon fiber precursor (PAN-based carbon fiber)
Limitations
- Highly flammable (LOI ~18%) — safety concern
- Low strength — not for demanding applications
- Poor abrasion resistance; pills easily
- Low moisture regain → static buildup; clammy feel in warm conditions
- Poor chemical resistance (acid + alkali sensitive)
- Heat-sensitive — softens and deforms at relatively low temperature
- Can yellow with prolonged heat exposure
- Cannot be melt-spun; dry/wet spinning uses organic solvents (DMF)
Yarn Engineering Guide
| Application | Type | Spinning | Key criteria |
|---|---|---|---|
| Sweaters / knitwear | Acrylic staple; high-bulk or regular | Woollen or worsted system | Wool-like hand; bulk; color; cost advantage over wool |
| Blankets / throws | Acrylic staple; high-bulk | Woollen; low twist for softness | Warmth; lightweight; washable (unlike wool); moth-proof |
| Outdoor fabrics (awnings, umbrellas) | Acrylic staple or filament | Ring or rotor; solution-dyed | UV resistance critical; solution-dyed for maximum color fastness |
| Socks / hosiery | Acrylic staple; often blended with nylon | Ring | Bulk and warmth; nylon for strength and abrasion at heel/toe |
| Carbon fiber precursor | Specialty PAN fiber; high molecular weight | Wet spinning; oriented | >90% of carbon fiber starts as PAN precursor; specialized production |
Summary
Acrylic's market position is defined by two unmatched properties: UV resistance and wool-like aesthetics at lower cost. It is the outdoor textile fiber and the affordable sweater fiber. Its limitations — flammability, low strength, pilling, and poor chemical resistance — confine it to applications where UV performance and hand feel matter more than durability. For the yarn engineer, the key acrylic technology is high-bulk yarn production via differential shrinkage — a unique capability among synthetic fibers. See the Textile Material framework.