Acrylic fiber is a widely used synthetic material for sweaters, scarves, hats, and other clothing items. Known for being lightweight, warm, wrinkle-resistant, and chemical-resistant, acrylic sweaters have become a popular winter wardrobe staple. Compared to natural fibers like wool or cotton, acrylic sweaters are more affordable and easier to care for. However, while acrylic fibers are generally resistant to shrinkage and durable, improper washing or exposure to high heat can still cause slight shrinkage or distortion. Understanding the properties of acrylic fibers and following proper care methods is essential to maintain the size and extend the lifespan of your sweater.
Do Acrylic Sweaters Shrink?
The short answer is: they can shrink, but usually only slightly. Acrylic fibers are synthetic polymers with a relatively stable molecular structure, meaning they are not as prone to significant shrinkage from water or heat as wool or cotton. However, under certain conditions, minor shrinkage or deformation can occur. Here’s a closer look at why:
Hot Water Washing
Acrylic fibers are made of long polymer chains that can slightly rearrange when exposed to water and heat. If the water is too hot, these chains move faster, and the spaces between fibers can tighten, causing the sweater to shrink overall or in certain areas. Simply put, hot water can “compress” the fibers, so it’s best to avoid washing acrylic sweaters in hot water.
High-Heat Drying
Exposing acrylic sweaters to high heat in a dryer can further shrink the fibers. The heat can even cause fibers to stick together locally, leading to uneven shrinkage or distortion. Compared to air drying, high-heat drying has a much stronger shrinking effect on acrylic fibers.
Friction and Aggressive Washing
Acrylic fibers have tiny surface fibers, and during washing, friction can cause them to tangle or compress, resulting in localized tightening and slight shrinkage. Vigorous hand washing or machine washing with other clothing increases this risk.
Using the Wrong Detergent
Detergents with strong bleach, enzymes, or high alkalinity can damage the protective layer of acrylic fibers, increasing surface friction or altering the fiber’s water absorption. This can make the pullover sweaters shrink or become stiff after washing.
In general, acrylic sweaters are less prone to shrinkage than natural fibers, but high heat, excessive friction, and harsh detergents should still be avoided to maintain stable sizing.
How to Prevent Acrylic Sweater Shrinkage
To keep your acrylic sweater in its original size and prolong its lifespan, follow these professional, science-based care tips:
1. Wash in Cold Water
Use water below 30°C (86°F) to hand wash your sweater. Avoid hot water, which can shrink the polymer chains. When hand washing, gently press the sweater instead of scrubbing to minimize friction and preserve the natural tension of the fibers.
2. Use Gentle Detergents
Choose detergents designed for synthetic fibers or delicate sweaters. These often contain low-foaming surfactants and fiber-protecting ingredients that reduce friction and chemical damage. Avoid bleach or enzyme-heavy detergents that can compromise the fiber’s molecular structure.
3. Avoid High-Heat Drying
The safest method is laying the sweater flat to dry, allowing fibers to settle under natural gravity. If you must use a dryer, select the low-heat or air-dry setting and reduce drying time to minimize heat-induced shrinkage.
4. Stretch Gently While Wet
When your sweater is still damp after washing, the fibers are soft and elastic. Gently stretch it back to its original dimensions and lay it flat to dry. This helps the polymer chains return to a more natural alignment and reduces post-drying shrinkage or distortion.
5. Store Properly
Hanging sweaters for long periods can cause shoulder stretching and shape distortion. Fold them flat in a dry, ventilated area to avoid moisture-induced shrinkage or mildew formation.
6. Avoid High-Heat Steam Ironing
Acrylic sweaters are not heat-resistant. Direct exposure to high-heat steam or irons can quickly shrink the fibers. If you need to remove wrinkles, use a low-heat steam iron or place a thin cloth over the sweater to protect the fibers.
7. Use a Mesh Laundry Bag
If you choose to machine wash, place the sweater in a soft mesh laundry bag to reduce mechanical friction and rubbing. Select the “delicate” or “wool” cycle to further minimize stress on the fibers, which helps prevent localized shrinkage.
Additional Tips
Follow care labels: Most acrylic sweaters sold in the U.S. come with care instructions—always follow them carefully.
Be cautious with blends: Sweaters blended with wool, cotton, or other fibers may behave more like natural fibers in terms of shrinkage and require extra care.
Low-heat ironing: High-heat steam can shrink acrylic fibers, so always use low heat or protective cloths when ironing.
Summary
Acrylic sweaters are generally resistant to shrinkage but not completely immune. High temperatures during washing or drying, excessive friction, and harsh detergents can still cause fibers to contract or distort. To maintain your sweater’s size and appearance:
-Wash gently in cold water
-Use mild, fiber-friendly detergents
-Lay flat to dry, avoiding dryers
-Stretch gently while damp
By understanding the characteristics of acrylic fibers and applying proper care methods, you can keep your sweaters comfortable, warm, and looking great for years. Correct care not only extends the life of your clothing but also helps keep your wardrobe organized and enjoyable to wear.
