Does Modal Shrink? The Truth About Modal Fabric Care
Modal shrinks less than standard viscose rayon — typically 3–5% in the first warm wash compared to 5–10% for regular viscose — because it is produced with a high-wet-modulus (HWM) manufacturing process that creates a more dimensionally stable fiber structure. However, modal is not shrink-proof: hot water above 40°C, high tumble dryer heat, and excessive mechanical agitation all increase shrinkage risk significantly.
What Makes Modal Different from Regular Rayon
Modal is a high-wet-modulus (HWM) viscose — a specialized type of rayon made from cellulose extracted from beechwood trees. Unlike standard viscose rayon, modal undergoes a modified production process that aligns the cellulose molecules more parallel to the fiber axis, resulting in a stronger, more stable structure.
The key difference lies in the degree of polymerization (DP) — the number of glucose units linked together in each cellulose chain. Modal has a higher DP than standard viscose, which directly translates to greater wet strength and improved dimensional stability during laundering.
Wet strength is where modal truly distinguishes itself from regular viscose. When immersed in water, modal retains significantly more of its dry strength — a critical factor in shrink resistance. Standard viscose rayon can lose 40–60% of its strength when wet, while modal loses far less due to its HWM classification. This places modal closer to Tencel (lyocell) in terms of wet performance, though Tencel still holds a slight edge due to its closed-loop manufacturing process.
The result: modal clothing maintains its original dimensions and shape through repeated washing cycles far better than standard rayon or viscose, though it still requires more careful handling than cotton or synthetic blends.
How Much Does Modal Shrink?
Modal shrinkage varies substantially based on wash temperature, cycle selection, and drying method. The following data reflects dimensional change measured according to AATCC TM135 (Dimensional Changes of Fabrics after Home Laundering), the industry-standard test method for evaluating textile shrinkage in domestic laundering conditions.
| Wash Condition | Modal Shrinkage | Standard Viscose Shrinkage |
|---|---|---|
| Cold hand wash (30°C) | <1% | 1–3% |
| Machine wash, cold (30°C) | 1–2% | 3–5% |
| Machine wash, warm (40°C) | 3–5% | 5–10% |
| Machine wash, hot (60°C) | 5–8% | 10–15%+ |
| Tumble dryer, high heat | Distortion risk | Significant damage |
These figures represent the average dimensional change observed across multiple wash cycles, with the highest shrinkage typically occurring in the first three wash cycles before stabilizing. Modal’s initial wash shrinkage is notably lower than standard viscose because the HWM manufacturing process pre-stretches the fibers, reducing the internal tension that causes shrinkage during subsequent laundering.
The critical temperature threshold for modal is 40°C. Above this point, the cellulose fibers begin to relax more significantly, and the risk of irreversible shrinkage increases sharply. Industry testing under AATCC TM187 (Accelerated Dimensional Changes) confirms that modal washed at 60°C consistently shows 5–8% shrinkage, whereas the same fabric washed at 30°C shows less than 2% shrinkage.
Modal vs. Tencel vs. Standard Rayon: Shrinkage Ranking
Within the cellulose fiber family, shrinkage resistance follows a clear hierarchy based on manufacturing process and fiber structure:
- Tencel/Lyocell: Lowest shrinkage of the three — closed-loop solvent-spinning process creates a highly ordered, crystalline fiber structure with wet strength approaching that of cotton. Typical shrinkage: <1% in cold wash, 1–3% in warm wash.
- Modal: Moderate shrinkage — better than viscose, not as stable as Tencel. The HWM process provides improved dimensional stability but does not match Tencel’s crystalline structure. Typical shrinkage: 1–2% in cold wash, 3–5% in warm wash.
- Standard Viscose/Rayon: Highest shrinkage of the cellulose fiber family. Conventional wet-spinning creates a less ordered fiber structure with significant internal tension. Typical shrinkage: 3–5% in cold wash, 10–15%+ in hot wash.
The manufacturing process explains this ranking precisely. Tencel uses a closed-loop NMMO (N-methylmorpholine N-oxide) solvent system that dissolves cellulose without chemical modification, then extrudes fibers in a water bath where the solvent is nearly 100% recovered and reused. This process produces fibers with very high molecular orientation and crystallinity. Modal, by contrast, uses the traditional viscose process (dissolving cellulose in alkali and carbon disulfide, then regenerating in an acid bath) but with modifications that increase wet modulus — still effective, but not as dimensionally stable as Tencel’s solvent-spinning approach.
To learn more about how these fibers compare, see our detailed guides on does viscose shrink and does rayon shrink.
How to Wash Modal Without Shrinking
Following these care guidelines will minimize shrinkage and extend the life of your modal garments:
- Water temperature: Machine wash cold at 30°C or below. This is the single most impactful variable for preventing modal shrinkage.
- Cycle selection: Use the gentle or delicate cycle. High-speed agitation in standard cycles increases felting shrinkage and fiber disruption.
- Detergent: Standard liquid or powder detergent is suitable for modal. Enzyme detergents are not required and add no benefit for modal care. Use normal amounts — excessive detergent residue can accelerate fiber degradation over time.
- Drying: Air dry by hanging or laying flat is the gold standard. If using a tumble dryer, select the lowest heat setting (40°C or below) and remove promptly when cycles complete. Prolonged low-heat tumbling is still less ideal than air drying.
- Ironing: If needed, iron at medium heat (150°C / 2-dot iron setting). Light steam works well for removing wrinkles without excessive pressure. Do not use the highest iron settings.
What to avoid: hot water above 40°C, high-heat dryer settings, and heavy mechanical agitation (such as hand wringing or twisting). Each of these factors independently increases shrinkage risk; combined, they can cause visible distortion and dimensional change beyond the figures in the table above.
Everyday Care Tips for Modal Clothing
Modal’s performance characteristics make it well-suited for frequently washed garments. Understanding these properties helps you care for modal clothing more effectively:
- Ideal for high-wash garments: Modal is commonly used in underwear, T-shirts, activewear, and sleepwear — items that benefit from frequent laundering. Its pilling resistance is a key advantage over cotton in these applications. Independent testing shows modal pills significantly less than cotton after 20 wash cycles due to its lower surface friction coefficient.
- Machine washable on gentle cycle: Most modal garments are fully machine washable when laundered correctly. Check the care label — many modal items now carry machine-washable symbols rather than the dry-clean-only labels common in early modal garments.
- Color bleeding caution: Dark modal garments may bleed color in the first wash. Wash dark modal separately or with like colors in cold water for the first 2–3 cycles until excess dye is removed. This is especially important for deep navy, black, and dark red modal items.
- Natural pilling resistance: Modal’s smooth fiber surface resists the fiber tangling that causes pilling. This is a genuine performance advantage — modal garments maintain their smooth appearance longer than cotton equivalents, reducing the need for fabric shavers or maintenance.
- Storage: Fold modal garments rather than hanging them. The soft, draping nature of modal means that hanging can cause the fabric to stretch at the shoulder seams over time, particularly in heavier garments like modal sweaters or robes.
For a broader guide to caring for eco-fibers like modal and Tencel, see our article on how to wash modal and Tencel: the eco-fiber care guide. And to understand the fiber itself, see our complete guide to what is modal fabric: beechwood fiber properties and care.
Frequently Asked Questions
Q: Is modal safe for the dryer?
A: Modal can go in the dryer on a low-heat setting, but air drying is always safer. High heat can cause more shrinkage than washing. Most modal garments that say “tumble dry” are fine on low heat for 1–2 cycles.
Q: Does modal shrink as much as cotton?
A: Cotton shrinks 3–10% on first wash; modal typically shrinks 1–5% depending on wash temperature. Modal has slightly better dimensional stability than cotton in most washing conditions.
Q: Can you put modal in a hot wash?
A: No — hot washing (above 40°C) significantly increases modal shrinkage. Stick to cold or warm (30°C) for modal garments to maintain their size and shape.
References
- Lenzing AG. (n.d.). Modal: The sustainable fiber from beechwood. Lenzing Group. Retrieved from https://www.lenzing.com/our-brands/modal
- AATCC. (n.d.). AATCC TM135 – Dimensional Changes of Fabrics after Home Laundering. American Association of Textile Chemists and Colorists. https://www.aatcc.org/test/methods/
- AATCC. (n.d.). AATCC TM187 – Dimensional Changes of Fabrics: Accelerated. American Association of Textile Chemists and Colorists. https://www.aatcc.org/test/methods/
- Wikipedia. (2024). Modal (textile). Wikipedia. https://en.wikipedia.org/wiki/Modal_(textile)
- Wikipedia. (2024). Lyocell. Wikipedia. https://en.wikipedia.org/wiki/Lyocell
- Cotton Incorporated. (n.d.). Textile Care Basics: Fabric Care Guidelines. CottonWorks. https://www.cottonworks.com/
