Optim™ fibre stretching technology, co-developed by Nanshan and The Woolmark Company, pre-stretches Merino wool fibres which are then spun into yarn before being woven to create wind and water-resistant fabric made from 100% Merino wool. Optim™ technology enhances the wool fibre’s natural water repellent properties through a tight weave, offering water resistance and wind protection for outdoor performance wear without chemicals treatments or PFAS.
Wind resistant
Reduced air permeability enhances wind resistance and improves wearer comfort.
Water resistant
Increased hydrostatic head enhances water resistance.
Naturally durable
Crisp and resilient handle makes the Merino wool fabric an ideal alternative to jacket fabrics made from synthetic fibres.
How it works
OPTIM™ SPINNING TECHNOLOGY
Optim™ fibre stretching technology uses Merino wool fibres which are spun into yarn before being woven to create wind and water-resistant fabric, made from 100% Merino wool, without using per- and polyfluoroalkyl substances – or PFAS.
The resulting Merino wool fabric is constructed at very high levels of thread density in warp and weft using fine Merino wool yarns in which the wool fibres have been stretched and temporarily set, during what is known as Optim™ processing. It is only when the fabric is wet-finished that the stretch is released causing the yarns to contract, thus leading to an extreme tightening of the fabric structure and the creation of the immensely dense fabric.
After optimising the spinning, weaving and finishing processes, the fabrics made from these stretched Merino wool fibres have enhanced water and wind resistant properties, while retaining all Merino wool’s fine properties such as breathability. These properties are achieved without any Durable Water Repellent chemical treatments like PFAS or “forever chemicals”. The fabric is also machine washable.
With France set to ban PFAS in clothing by 2026, Optim™ technology offers the perfect PFAS-free, water-resistant natural wool solution. No DWR treatments, no harmful "forever chemicals" - just pure Merino wool innovation, engineered for wind and water resistance.
Woolmark’s technical innovation team has continued to work with the Nanshan R&D team on the development of the Optim™ fabric, which is now commercially available in six different weights and options. The differing weights and the inherent properties of the wool fibre allow for interest from both the activewear, streetwear and smart-casual sectors of the global apparel industry.
Contact the Woolmark Technical Team for more information.
Optim™ Classic
Optim™ Classic is the original range of water-resistant wool fabrics, engineered with Optim™ fibre stretching technology to enhance wind and water resistance - all without chemical treatments. Made from 100% Merino wool, this breathable, high-performance fabric repels water while maintaining durability and comfort.
Ideal for suits, jackets, blazers and pants, Optim™ Classic delivers protection, versatility and long-lasting performance. Available in three distinct weights - 180g/m² plain weave, 240g/m² warp rib and 265g/m² gabardine - this premium fabric offers a refined feel with built-in weather resistance for modern applications.
Optim™ Luxury
Optim™ wool is expertly blended with luxurious natural fibres (10-20%) to create high-performance fabrics with unique textures and finishes. These blends maintain Optim™’s signature wind and water resistance, offering both functionality and elegance, making them ideal for suits, jackets, blazers and pants.
- Optim™ wool/mohair - A glossy, lightweight fabric with a delicate, refined finish.
- Optim™ wool/cashmere - A blend of natural warmth, gentle lustre, and timeless elegance.
Optim™ Stretch
Optim™ Stretch blends Optim™ wool with spandex, elastane, or other stretch fibres to create wind- and water-resistant wool fabrics with added elasticity. Engineered for comfort, resilience, and superior drape, these fabrics provide natural weather protection while allowing freedom of movement. Ideal for outdoor activities, Optim™ Stretch offers breathable, flexible, and durable performance without DWR treatments.
Optim™ Blend
Optim™ wool blended with synthetic fibres creates high-performance outdoor fabrics that offer natural wind and water resistance at a more competitive price. Designed for durability and weather protection, these fabrics maintain breathability and resilience without compromising performance. Available in ripstop and pinstripe weaves, this category delivers versatile, long-lasting protection for outdoor applications.
Optim™ Fancy
Optim™ Fancy is a collection of distinctive Optim™ wool fabrics with natural water resistance, featuring satin, seersucker, stripes and other textured weaves. Expanding the possibilities of water-resistant wool, this range brings breathability, comfort and style to a variety of applications, including base-layer shirts, dresses and more. Available in 100% wool and luxurious wool blends such as wool/silk and wool/cashmere, Optim™ Fancy offers versatility and elegance while maintaining its signature weather-resistant properties.
Optim™ Double
Optim™ Double fabrics use double-layer physical composite technology to create dual-sided wool fabrics. The smooth, compact texture on the face side provides enhanced wind repellence and water and stain resistance, while the bulky brushed finish on the backside offers superior heat storage and warmth. The soft inner side eliminates the need for lining, making it an ideal choice for winter jackets and coats with natural weather protection and insulation.
All above OPTIMTM fabric images courtesy of Nanshan.
