Viscose (Regenerated Cellulose / 黏胶纤维)
Viscose (rayon) is the original man-made fiber, commercialized in the 1890s. It is made by dissolving wood pulp or cotton linters in a chemical process — NaOH + carbon disulfide (CS₂) — and wet-spinning the viscous solution into an acid coagulation bath. With ~6.7 million tons produced in 2024 (~80% of all MMCFs), it is the dominant regenerated cellulose fiber: cost-effective, highly absorbent, and silk-like, but with the critical limitation of losing roughly half its strength when wet.
Quick Facts
| Type | Regenerated cellulose (man-made cellulosic fiber / MMCF) |
| Raw material | Wood pulp (beech, eucalyptus, pine, bamboo), cotton linters; dissolved via NaOH + CS₂ → sodium cellulose xanthate |
| Commercialized | 1891 (Cross, Bevan, Beadle); first commercial "artificial silk" |
| Global production (2024) | ~6.7 million tons (~80% of MMCFs; ~5% of all fibers) |
| Cross-section | Irregular serrated (锯齿形); pronounced skin-core structure |
| DP (degree of polymerization) | 250–400 (vs. cotton: 9,000–15,000) |
| Crystallinity | 30–40% (vs. cotton: 65–70%) |
| Moisture regain | 12–14% (highest among common textile fibers; more absorbent than cotton) |
| Density | 1.48–1.53 g/cm³ |
| Key trade names | LENZING™ ECOVERO™ (sustainable viscose), Birla Viscose, ENKA® Viscose |
Properties
| Property | Value / Rating | Engineering implication |
|---|---|---|
| Dry strength | 1.5–2.4 cN/dtex · ★★☆☆☆ | Lower than cotton; adequate for general apparel but not for high-stress applications |
| Wet strength | 45–55% of dry · ★☆☆☆☆ | Critical weakness: garments weaken dramatically when wet; handle with care in laundering |
| Elongation | 15–25% dry; 20–30% wet · ★★★☆☆ | High stretch for a cellulosic fiber; wet elongation increases → dimensional instability; fabric grows and sags |
| Moisture absorption | 12–14% · ★★★★★ | Best of all common fibers; excellent comfort in hot weather; dye uptake is superior |
| Elastic recovery | Poor · ★☆☆☆☆ | Wrinkles easily; often blended with polyester or resin-finished |
| Abrasion resistance | Poor, especially wet · ★☆☆☆☆ | Not for high-wear applications; wet abrasion is particularly damaging |
| Dyeability | Excellent · ★★★★★ | Direct, reactive, vat, and sulfur dyes; brighter colors and deeper shades than cotton; good color fastness |
| Chemical resistance | Cellulose chemistry · ★★★☆☆ | Alkali-resistant (but less than cotton); acid-sensitive; oxidizer-sensitive |
| Thermal behavior | Decomposes ~180°C · ★★★☆☆ | Does not melt; chars (cellulosic); no melt-drip hazard |
| Biodegradability | ★★★★★ Yes | 100% biodegradable; cellulose II structure decomposes faster than native cotton cellulose |
Advantages vs. Limitations
Advantages
- Highest moisture absorption among common fibers (12–14%)
- Excellent dyeability — bright, deep colors with good fastness
- Soft, silk-like hand at low cost
- Controllable fiber length and fineness
- Biodegradable and from renewable feedstock
- Lowest cost among MMCFs (~0.7–1.0× cotton)
- Comfortable in hot, humid conditions (high absorbency)
- ECOVERO™ variant offers improved environmental performance
Limitations
- Severe wet strength loss (~50%) — critical handling limitation
- Poor elastic recovery → wrinkles, poor shape retention
- High wet elongation → fabric grows and sags
- CS₂ and H₂SO₄ in production — environmental concern
- Lower strength than cotton, Modal, and Lyocell
- Poor abrasion resistance, especially when wet
- Skin-core structure creates uneven dye penetration in thick fabrics
- Fabric may shrink significantly without proper finishing
Yarn Engineering Guide
| Application | Form | Spinning | Key criteria |
|---|---|---|---|
| Fashion apparel (dresses, blouses) | Staple, 1.3–1.7 dtex, 38 mm | Ring or rotor; often blended with polyester | Drape and dyeability; polyester adds wet strength and wrinkle resistance |
| Linings | Filament (viscose rayon) or staple | Filament weaving or staple spinning | Smooth surface; anti-static finish; cost-effective |
| Nonwovens (wipes, hygiene) | Staple, 1.7–6.7 dtex | Carded → hydroentangled | Absorbency; biodegradability; low cost critical |
| Fashion knitwear | Staple, 1.3–1.7 dtex | Ring, compact; low twist | Soft hand; good drape; often blended with nylon or elastane |
Summary
Viscose is the volume workhorse of regenerated cellulose — affordable, absorbent, and beautifully dyeable. Its fatal flaw is wet strength: at ~50% of dry strength, it is the weakest wet performer among common fibers. This dictates its dominant use pattern: blended with polyester for strength, used in applications where garments are not stressed when wet, or chosen for precisely the properties where it excels — drape, color, and absorbency. See the Textile Material framework for substance–form–performance logic.