| Hard shells are known for their tough waterproof outer fabrics and are the most common choice for an all around ski jacket. Un-insulated hard shells are popular as you can vary the separate insulation layers you wear underneath to match the weather conditions and your anticipated activity level on any given day. Hard shells are the skier’s choice in wet climates like the Pacific Northwest, like the Marmot Fjell jacket shown below.
The outer fabric of a hard shell is usually a woven nylon or polyester. A microporous polyurethane coating or laminate is applied to the inside of the shell fabric. The hard shell manufacturers either use the GORE-TEX® brand material or a one of their own design that carries their own brand name. Since the GORE-TEX® patent expired, many new materials have come on the market. Brand names for these coatings and laminates are GORE-TEX®, eVent™, Hyvent™, Omni-tech™ and others. The principal behind these materials are basically the same.
The idea behind these materials is to enhance the jacket fabric so that it is both waterproof and breathable. There are millions of tiny holes in the coatings and laminates which are small enough to keep liquid water from passing through, but are large enough to allow water vapor to escape. This allows water vapor from body heat, wet clothes or sweat to evaporate through the fabric while no water from the outside can get in.
Coatings are applied as a liquid. Laminates are a solid layer which is fused to the back of the fabric. Coatings and laminates act as a barrier to keep water droplets from penetrating the fabric while maintaining a microporous structure that allows much smaller water vapor molecules, generated from body heat, to escape to the outside, keeping you dry.
Different coating mixtures and laminate materials are used to provide the varying degrees of waterproofness and breathability levels available in different jackets. A less porous mixture creates a more waterproof ski jacket. Some laminates are also used as an interior finish, thereby eliminating the need for a separate lining.
The outside of the shell will be treated with a durable water resistant (or repellent) coating (DWR) to protect the outer material from water saturation. DWR is a liquid applied to the outside of the fabric. DWR keeps the fabric from `wetting out` or saturating the fabric from the exterior which will reduce the breathability of the coating or laminate. DWR acts like hair causing water to bead up and roll off the jacket. Beading makes the water molecules too big to fit through the pores in the fabric.
The DWR finish will carry its own rating level. For example: 80/20 DWR means that after 20 washings, the coating retains 80% of its original DWR quality. Teflon is a common component of DWR. Both hard shells and soft shells use DWR. DWR provides a stain resistant finish to the face of the fabric, allowing you to easily clean spots and spills with soap.
Some other fabric info:
GORE-TEX® Hard shells come in 2 layer and 3 layer construction.
2-layer construction: a specific GORE-TEX® membrane is laminated to the inside of the outer material. The inside of the membrane is protected by a separate lining
3-layer construction: a specific high-performance GORE-TEX® membrane bonded to a tough outer material and a specially developed robust inner lining
Taffeta – taffeta is a Persian word meaning ‘twisted woven’ and usually refers to a crisp, smooth woven silk or synthetic fabric (Backcountry, December 2007 Anatomy of a Softshell by Drew Pogge, p 102)
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