Lyocell (Solvent-Spun Regenerated Cellulose / 莱赛尔 / Tencel™)
Lyocell is the most advanced regenerated cellulose fiber. Unlike viscose and modal, which use chemical derivatization (CS₂-based xanthation), Lyocell directly dissolves cellulose in N-methylmorpholine N-oxide (NMMO), a non-toxic tertiary amine oxide solvent, and spins the solution through a dry-wet (air-gap) spinning process. The solvent is recovered at >99.5% in a closed loop. The result is a fiber with near-cotton dry strength, minimal wet strength loss (~15%), a uniform round cross-section with no skin-core structure, and the best environmental profile among MMCFs. Global production reached ~0.4 Mt in 2024 and is growing at 6%+ CAGR.
Quick Facts
| Type | Solvent-spun regenerated cellulose (NMMO process); closed-loop manufacturing |
| Solvent | N-methylmorpholine N-oxide (NMMO) — non-toxic, biodegradable, >99.5% recovered and reused |
| Spinning method | Dry-wet (air-gap) spinning: solution extruded through air gap → coagulated in water bath |
| Invented / commercialized | 1980 (Akzo-Nobel patent); 1989 CIRFS named "Lyocell"; Courtaulds Tencel® 1992; Lenzing acquisition 2004 |
| Global production (2024) | ~0.4 million tons (~5% of MMCFs; fastest-growing MMCF type at ~6.2% CAGR) |
| Cross-section | Round or oval; uniform; no skin-core; smooth surface |
| DP | 500–600 (highest among MMCFs; closest to native cellulose) |
| Crystallinity | 50–55% (vs. viscose: 30–40%; modal: 40–45%) |
| Moisture regain | 11–13% |
| Key trade names | Tencel™ (Lenzing), LENZING™ Lyocell, Birla Excel (Aditya Birla) |
Properties
| Property | Value | Engineering implication |
|---|---|---|
| Dry strength | 3.5–4.2 cN/dtex · ★★★★☆ | Comparable to cotton; the strongest MMCF; can be used in 100% form for durable garments |
| Wet strength retention | ~85% of dry · ★★★★☆ | Best among all MMCFs; minimal wet strength loss; near-cotton wet performance |
| Elongation | 10–15% · ★★★☆☆ | Lower than viscose (15–25%) → better dimensional stability; less fabric growth |
| Moisture absorption | 11–13% · ★★★★☆ | Excellent comfort; slightly below viscose but still far above cotton and synthetics |
| Fibrillation | High (untreated) · ★★☆☆☆ | Unique characteristic: fiber surface splits into micro-fibrils under wet abrasion; can be exploited for peach-skin finishes or controlled via cross-linking (Tencel™ A100 anti-fibrillation treatment) |
| Dyeability | ★★★★☆ Good | Similar to other MMCFs; fibrillation can create special wash-down and color effects |
| Elastic recovery | Better than viscose · ★★★☆☆ | Still imperfect; higher modulus gives better shape retention; often blended for wrinkle resistance |
| Anti-microbial | ★★★★☆ Natural | Lyocell naturally inhibits bacterial growth (moisture management + smooth surface); no chemical treatment needed |
| Environmental | ★★★★★ Best among MMCFs | NMMO non-toxic; closed-loop >99.5% recovery; biodegradable; FSC-certified wood; lowest environmental footprint of all MMCFs |
Advantages vs. Limitations
Advantages
- Strongest MMCF — dry strength comparable to cotton
- Best wet strength retention among MMCFs (~85%)
- Best environmental profile: closed-loop, non-toxic solvent, biodegradable
- Round, uniform cross-section — smooth, clean surface appearance
- Natural anti-microbial properties
- Can be fibrillated for unique surface effects (peach-skin, suede-like)
- Good dimensional stability (lower elongation than viscose)
- Growing production — fastest-growing MMCF segment
Limitations
- High fibrillation tendency (untreated) — can be a defect if not controlled
- Higher cost than viscose (~1.5–2× viscose; premium pricing)
- Limited production volume (~0.4 Mt vs. viscose's 6.7 Mt) — supply constraints
- Still loses ~15% strength when wet (cotton gains strength)
- Anti-fibrillation cross-linking (Tencel™ A100) reduces softness slightly
- Higher energy consumption in production vs. conventional viscose (offset by environmental benefits)
Yarn Engineering Guide
| Application | Form | Spinning | Key criteria |
|---|---|---|---|
| Denim (premium comfort) | Lyocell staple, 1.3–1.7 dtex; often blended with cotton | Rotor or ring | Softness + drape; 20–40% Lyocell popular in comfort-stretch denim |
| Activewear / sportswear | Lyocell staple or filament; microfiber | Ring or filament knitting | Moisture management; anti-microbial; biodegradability for eco-positioning |
| Sustainable fashion (100% Lyocell) | Lyocell staple, 1.3–1.7 dtex | Ring or compact | Full environmental story; unique drape; fibrillation can be design feature |
| Home textiles (sheets, duvet covers) | Lyocell staple; often blended with cotton | Ring; compact for smoothness | Smooth, cool hand; moisture management; anti-microbial for bedding hygiene |
| Technical wipes / industrial cleaning | Lyocell staple; 1.7–3.3 dtex | Hydroentangled nonwoven | High wet strength; low lint; controlled fibrillation for cleaning efficiency |
Summary
Lyocell is the premium environmental choice in regenerated cellulose — best-in-class wet strength, near-cotton dry strength, a closed-loop non-toxic manufacturing process, and unique fibrillation properties that can be harnessed or controlled. Its main constraints are cost and limited production capacity relative to viscose. For the yarn engineer, the key decision is fibrillation management: untreated (standard Lyocell, fibrillation exploited for effect) vs. cross-linked (Tencel™ A100, fibrillation suppressed for clean surface). See the Textile Material framework for substance–form–performance logic.