Fibres · Synthetic
Acrylic
The synthetic that imitates wool: cheap, brightly coloured and easy to wash, it is the workhorse of carefree projects. It asks little in return, but over time it loses elasticity, pills and dislikes heat, which deforms it.
Translated from Italian. A native knitter has not reviewed this translation yet.
History
It was born in the laboratory: polyacrylonitrile was developed in the 1940s and the first commercial acrylic fibre, DuPont's Orlon, reached the market in the early 1950s, followed closely by Acrilan and the European Dralon. From the start it was offered as a cheap substitute for wool, and within a few decades it took over mass-market knitwear, low-cost hand-knitting yarns and blankets. It is the fibre that made bright colour affordable for everyone.
How the yarn is made
The starting point is petroleum: the acrylic polymer is dissolved and then extruded through a spinneret, by wet or dry spinning, giving a continuous filament. To imitate wool the filament is crimped and cut into staple, so that it can be spun like a natural fibre; it often ends up blended with wool or cotton, to lower cost and weight and add washability.
Why it is prized
It is not a luxury fibre, it is a practical one: its value lies in price, colour and lightness. It costs little, takes very bright and stable shades, weighs little on the body, does not felt and stands up well to the washing machine. Blended with fine fibres it lowers their price and improves their wash resistance, which is why it is found everywhere in mass-market knitwear.
Dyeing
Excellent in result, particular in method: acrylic is dyed with specific dyes, basic or cationic, often already at the spinning stage. The result is very bright, even colours with good fastness to light and washing, hard to achieve with the same brilliance on natural fibres.
Care
It is an easy fibre: it machine-washes, dries quickly and does not attract moths. Its enemy is heat, because it is a thermoplastic material: a hot iron or tumble dryer softens it and deforms it permanently. It pills with rubbing and builds up static electricity; better to wash it cold, iron it barely warm or not at all, and avoid the tumble dryer.
End of life
This is its weakest point: it is not biodegradable and every wash releases microplastics that end up in the water. Recycling exists but is limited and not widespread; the recycled version, when certified, is preferable to virgin fibre, but it remains a material the environment does not reabsorb.
How to recognise it
| Hand | It can resemble wool, but to the touch it is cool and less springy, with a hint of dry squeak between the fingers; it tends to build up static and spark. |
|---|---|
| Look | Very even and regular, sometimes with an artificial lustre that is a little too perfect; with wear its surface becomes covered in small pills. |
| Behaviour | It is warm but does not breathe and does not manage moisture as wool does; it tends to pill and, under heat, to deform rather than recover. It does not felt and keeps its colours bright for a long time. |
| Burn test | Unmistakable synthetic signature: it does not burn but melts, shrinking away from the flame with black smoke, an acrid chemical smell, and leaves a hard plastic bead. This is the test that instantly exposes fake wool or cashmere. |
| Home tests | Burn test: if it melts into a hard bead instead of crumbling into friable ash, it is neither wool nor cashmere · Touch test: cool, a little squeaky and sparking with static · Heat test: it dislikes a hot iron and deforms, where wool holds up |
| Confused with | The wool and cashmere it imitates: but in the flame it melts into a hard bead and it is cool to the touch, while wool burns slowly and smells of burning hair · Other synthetic fibres (polyester, polyamide): they all melt, and a certain distinction requires the laboratory |
| Only in a lab | To tell acrylic apart from other synthetics and to measure its percentage in blends you need the laboratory, with FTIR spectroscopy or quantitative analysis according to ISO 1833. |
Physical facts
| Property | Value | Source |
|---|---|---|
| elastic memory | Medium (but gives over time) | research |
| sag | Low | research |
| halo | Low | research |
| felting risk | None | research |
| fineness (µm) | — | research |
| moisture regain (%) | 1.5 | research |
| typical shrinkage (%) | 0–3 | estimate |
| staple length (mm) | — | research |
measured = a measurement with a reference · iso = a standard · research = a verified source · estimate = plausibility only
For the fabric engine
| friction coefficient (µ) | 0.4 | measured |
|---|---|---|
| density (g/cm³) | 1.17 | measured |
| Young's modulus (GPa) | 5.0 | measured |
| specific bending stiffness (dyn·cm²/tex²) | 0.29 | estimate |
Good for
cheap, colourful knitwear · blends for washability and cost · garments that must not felt · bright, stable colours · low-cost first projects
Less good for
garments that need to breathe · garments exposed to heat (ironing, tumble dryer) · projects that must last and keep their shape · anyone looking for natural, biodegradable fibres