Engineered (Composite) Yarns
by John Simmons of World Fibers
Engineered composite yarns are yarns made with two or more components (i.e Kevlar® and steel). These yarns have allowed glove manufacturers to make gloves with higher levels of cut resistance, without sacrificing comfort or dexterity, than with high-strength fibers, such as Kevlar® or Dyneema® alone.
Cut resistance in knitted gloves is influenced by four factors:
Strength: Examples of high-strength yarns would be Dyneema® or Kevlar®
Hardness (dulling): An example of hard yarn would be stainless steel, which is often a primary component in composite yarns.
Lubricity (slickness): slippery yarns such as Spectra® or Dyneema® allow a blade to slide over their surface without cutting through.
Rolling action (knit construction) : Most knit gloves allow the individual yarns to ‘roll’ as a sharp edge slides over them, producing somewhat of a ball-bearing effect. The edge slides across without cutting through the material.
Typically, the more of these factors that can be engineered into a yarn, the more cut resistant it will be. For example, an engineered yarn may consist of high molecular-weight polyethylene (HMPE) such as Dyneema®, which is both high strength and slick; and stainless steel, which is hard, and then knit in to a seamless glove, which provides ‘rolling’. Taken together, these characteristics result in a material that is far more cut resistant than a material made with only one component.
Further design considerations may be color, grip, moisture management, or other characteristics that engineered yarns can provide in a special-purpose glove. Engineered yarns are typically used in applications requiring higher levels of cut resistance (ASTM Level 3 or higher), such as sharp or heavy sheet-metal handling, glass handling, or
meat processing where sharp blades are used.
DuPont™ Kevlar®: A Cut above the rest in industrial cut protection
Kevlar® brand fiber is incredibly strong, tough, light, flexible, heat, flame and cut resistant. This unique combination of high-performance properties makes Kevlar® fiber the solution for many demanding applications:
• Ballistic vests & hard armor
• Cut and heat-resistant gloves & sleeves
• Firefighter turnout gear
• Ropes & cables
• Tires / Mechanical rubber goods
In addition to the impressive list of inherent properties, Kevlar® is available in a wide range of fiber forms providing protective-apparel manufacturers with plenty of design flexibility. These products include staple and staple-based spun yarns, flat and textured continuous filament yarns, and engineered blends that incorporate other fibers, materials and colors. Consequently, end-users can rely on the protection offered by products made with Kevlar® regardless of their industrial application. Knitted Kevlar® gloves and sleeves range from ultra-light 18-gauge cut-resistant gloves and sleeves to heavyweight 7-gauge terry knits for cut or heat-resistant gloves, sleeves and mitts. Cut and thermal protective gloves and garments are also produced from cut and sewn woven fabrics made from Kevlar® which can provide good thermal-insulation properties for hot or cold working environments.
Another important consideration when selecting the appropriate PPE is the care, cleaning and disposal of the product. The ability to launder and recondition gloves made of Kevlar® has been an important element of the overall value proposition and widespread industrial acceptance. Conventional industrial laundering and dry cleaning methods are used to clean the most challenging greases and oils and the cut resistance of Kevlar® is not affected. Some oleophatic fibers like HPPE can stain when exposed to these same oils and grease. Although products made with Kevlar® are resistant to most chemicals and solvents, strong acids, bases, and certain oxidizers like chlorine bleach, cause degradation of the fiber. The elimination of chlorine bleach in the cleaning of industrial apparel does not hinder the ability to clean it. Alternatives like oxygen bleaches can be used without issue. Consult the Kevlar(R) laundering guide for more detailed information.
Advantages of Dyneema® in Protective Gloves
by Giovanni Henssen, Application Manager, High Protective Textiles, DSM Dyneema
Dyneema® is fifteen times stronger than steel on a weight-for-weight basis, and is commercially produced by DSM Dyneema. It is made from ultra-high molecular-weight polyethylene (UHMW-PE) and has a very high cut resistance compared to both natural fibers (cotton, leather), and other man-made fibers.
Protective gloves made withDyneema® yarn can provide the following benefits:
The use of PPE should not be viewed as a cost, but as a cost-saver, preventing hand injuries and saving more money than not buying any gloves at all. If total system costs are taken into account, Dyneema® offers a cost-effective solution thanks to it’s extremely high longevity which is related to:
High Abrasion Resistance
Thanks to the smoothness and high-crystalline properties of the Dyneema® fiber, the abrasion resistance is extremely high and cannot be matched by any other fiber. Tests have demonstrated that gloves made with Dyneema® have up to twenty-times better abrasion resistance than gloves made, for example, with Aramid (spun) yarns.
This characteristic has a significant and direct effect on the durability and longevity of the glove.
Protective gloves are often exposed to sharp objects that can abrade them. The more a glove is abraded, the less protection it offers. Naturally, the higher the abrasion
resistance a glove offers, the longer the wearer is protected consistently during the
lifetime of the glove. As can be seen in figure 1, gloves with Dyneema® offer this kind of
consistent cut performance.
For knitted products (like gloves), puncture resistance typically is very low, which increases the importance of the tear resistance of the fiber used in the glove. Puncture and tear resistance go hand-in-hand. The combined performance of cut, abrasion, puncture and tear defines the actual performance of gloves in use. But the level of comfort a glove offers will define whether or not one will actually wear them.
HAGANE COIL™ Technology
“Hagane Coil” is stainless steel composite yarn developed by SHOWA GLOVE Co. for cut protection.
It can provide various strengths (e.g. cut protection, flexibility etc…) by combining yarns which have differential features.
U.S. Patent No. 7762053
EU Patent No. ○○○○○
*Please confirm other Patents if you use.