Vinylon (PVA / 维纶 / Polyvinyl Alcohol Fiber)
Vinylon is polyvinyl alcohol (PVA) fiber — the only water-soluble synthetic fiber in its raw form. Before textile use, PVA must be acetalized (typically with formaldehyde) to cross-link the hydroxyl groups and render the fiber insoluble in hot water. Vinylon was once called "synthetic cotton" for its relatively good moisture absorption (~5%) — the highest among common synthetics, second only to nylon. However, poor elasticity, dull dyeing, pilling tendency, and competition from polyester have driven it to near-extinction as a standalone fiber: global production is only ~300,000 tons/year, concentrated in China, Japan, and North Korea. Its modern relevance lies in two niches: water-soluble PVA filament as a sacrificial support yarn in co-spinning, and high-strength/functional PVA for industrial textiles.
Quick Facts
| Type | Synthetic (addition polymer); polyvinyl alcohol; must be acetalized (缩醛化) for textile use |
| Chemistry | Polyvinyl alcohol (PVA) → acetalized with formaldehyde → cross-linked, water-insoluble fiber; retains some –OH groups for moisture absorption |
| Commercialized | 1940 (Japan: Kuraray); early synthetic fiber alongside nylon |
| Global production | ~300,000 tons/year; China ~30,000 t; declining; nearly exiting the commodity fiber market |
| Moisture regain | 4.5–5.0% (highest among common synthetics after nylon; "synthetic cotton") |
| Density | 1.26–1.30 g/cm³ |
| Strength | Standard: 2.5–4.0 cN/dtex; high-tenacity: up to 7.0 cN/dtex (industrial grades) |
| Key trade names | Kuralon® (Kuraray), Vinylon, Vinal (US FTC name) |
Properties
| Property | Rating | Engineering implication |
|---|---|---|
| Moisture absorption | ★★★★☆ Best among cheap synthetics | ~5% regain — the reason it was called "synthetic cotton"; better comfort than polyester and PP |
| Chemical resistance | ★★★★★ Excellent | Resists seawater, soil burial, alkalis, and many chemicals; near-indestructible in harsh environments — both a strength and an environmental problem |
| UV / light resistance | ★★★★☆ Good | Better than nylon and PP; suitable for outdoor applications |
| Strength | ★★★★☆ Good (high-tenacity available) | Industrial high-tenacity PVA reaches 7 cN/dtex; competitive with nylon for ropes and reinforcements |
| Water solubility (raw PVA) | Unique property | Unacetalized PVA dissolves in water — used as sacrificial support yarn (伴纺) in co-spinning, then washed out |
| Elastic recovery | ★★☆☆☆ Poor | Low elasticity; fabric deforms and wrinkles; one reason for its market decline |
| Dyeability | ★★☆☆☆ Poor / dull | Dyes appear dull and flat; limited color palette; cannot match polyester or nylon vibrancy |
| Heat resistance (wet) | ★★☆☆☆ Poor | Softens and deteriorates in hot water (even acetalized); limits laundering and finishing |
| Pilling tendency | ★★☆☆☆ High | Prone to pilling and fuzzing; another factor in market decline |
Niche Applications
| Application | PVA type | Why PVA |
|---|---|---|
| Water-soluble support yarn (伴纺) | Raw (unacetalized) PVA filament | Spun together with low-strength fibers (e.g., wool, protein fibers); PVA dissolved in finishing → creates lightweight, soft fabrics |
| Protein/polymer blend carrier | PVA as matrix (60–80% of blend) | Most "regenerated protein fibers" are actually PVA/protein blends; PVA provides spinnability and strength; protein provides branding and bio-content |
| Cement reinforcement | High-tenacity PVA staple | Alkali-resistant; strong bonding to cement matrix; used in engineered cementitious composites (ECC) |
| Ropes, fishing nets (specialty) | Acetalized PVA filament | Seawater-resistant; high strength; used where nylon's UV sensitivity is a problem |
Summary
Vinylon is a fiber in decline — once promising as "synthetic cotton" but outcompeted by polyester on cost and performance. Its surviving niches are precisely where its unique properties (water solubility, alkali resistance, chemical stability) are essential rather than optional. For the yarn engineer, PVA's value today is primarily as a sacrificial process fiber (soluble PVA for co-spinning) and as a matrix carrier in protein-blend fibers. See the Textile Material framework.