Introduction 

NEMO prides itself in designing innovative outdoor gear. We only bring products to the market that improve the user’s experience and are superior to gear that already exists. Sometimes these improvements come by way of clever product design, and other times we are able to delve deeper and rethink the materials themselves. 

Tent fabrics are particularly technical. These materials form the major component of a shelter that must protect the user from wind, rain, and snow — all while remaining flexible and lightweight enough to stow away and transport. Tents must withstand both UV exposure when in use and hydrolysis (breaking down of the coatings by water) when packed away wet. For these reasons, tent fabric performance is a critical element when it comes to enjoying time outdoors. 

In addition to performance, we take responsibility for our environmental impacts and we are committed to delivering to our customers products they can be proud to own. We see improved sustainability, particularly by reducing greenhouse gas emissions to combat climate change, as a key part of making the best products possible. The goal for OSMO, our new family of fabrics, was to develop a tent fabric that reduces environmental impact and maximizes performance simultaneously, without compromise. 

During two years of materials development, we broke down the fabric to its components and optimized each part to create a composite material that is greater as a whole. We explored every element of fabric construction, from the yarns and weave to the coatings and finishes, with the goal of improving performance and sustainability. 

Here is a look into our development process and a chance to learn more about the benefits of our suite of patent-pending OSMO fabrics.

 Figure 1: Photograph of a finished OSMO fabric. The different colored yarns are the result of using nylon and polyester in this composite construction.

 

Background 

Making a tent fabric starts with producing the yarns. Polymer granules are mixed and melted, and the melt is then pressed through a spinneret, cooled, drawn, and finally collected on a spool. Chemistry, size, shape, and number of filaments are important physical characteristics of a yarn, along with the temperature, time, and tension of the yarn throughout the process. 

The next step is to weave the yarn into a fabric. Here, the weave structure is determined by the interlacing of yarns. The structure of the weave determines how the yarns interact under loads and can affect tear strength, stretch, and puncture strength. 

After weaving, various finishes are applied to a fabric. For a tent fabric, these generally include a polyurethane coating for waterproofing and a hydrophobic finish for water repellency. This stage can also include dyeing and other finishing steps. 

 

Development 

We worked with the best mill partners in the industry to develop the OSMO tent fabrics. We also worked directly with the mill suppliers to bring new yarns, coatings, and finishes into the process. Over 100 development samples were made and tested against a battery of performance specifications. With each sampling round, the fabrics were further refined until they exceeded our performance requirements.  

 

Physical Description 

OSMO fabric is made from a unique composite weave of low-denier nylon and polyester yarns (Figure 1). This composite approach harnesses the benefits of each individual yarn. Hydrophobicity, low water absorption, and low wet stretch are provided by the polyester yarns; tensile strength and tear resistance are offered by the nylon yarns. A proprietary polyurethane coating formulation on the back of the fabric imparts resilient waterproofness, while a combination of fluorine-free water repellent and/or silicone seals the face of the fabric behind a water-shedding hydrophobic barrier.  

To our knowledge, OSMO is the first and only composite polymer fabric in the tent category, and just one example of NEMO’s commitment to innovation and ever-evolving product design. 

 

Performance 

Tents are portable shelters, one of the few things protecting a user from the potentially harsh elements of the outdoors. A critical function of a tent is keeping the user dry, and this is managed by a few key performance metrics: waterproofness, water repellency, wet stretch resistance, and hydrolysis resistance. Strength is also a critical metric for tent fabric given its exposure to wind and the weight of potential snow, plus the abrasion and puncture a tent floor may be subjected to. 

 

Water Repellency 

Water repellency allows tent fabrics to shed water rather than absorb it. This is important for keeping users dry and maintaining the physical characteristics of the tent, as wet fabrics become heavier and will typically stretch and sag. OSMO water repellency performance was measured using multiple methods that wet the fabric and then measure the amount of water remaining on the fabric after agitation. The durability of the water repellency was determined by following standard industry test methods of washing the fabric, which degrades fabric performance in a controlled manner, and then measuring the performance again. 

Repeated washing and measuring can reveal a trend in performance, as seen in Figure 2, which shows the degradation in water repellent performance for OSMO fabric compared to an average tent fabric. (The data is normalized with respect to the initial performance to emphasize the change in water repellant performance.) The data shows OSMO tent fabric water repellency is 4x more lasting than the average tent fabric. It should also be noted that OSMO fabrics start with better initial water repellant performance, with an average of 92.5, compared to an industry average rating of 83.6 according to AATCC 22, another industry-accepted test. 

The bottom line is that OSMO fabrics are more water repellent from the start and will stay that way longer than standard tent fabric, thanks to a combination of hydrophobic coatings, hydrophobic yarns, and weave construction. 

 

Figure 2: Durability of tent fabric water repellent.

 

Wet Stretch 

Minimizing wet stretch is important for keeping your tent fly taut. A loose tent fly can press against the inner tent fabric and transfer condensation to the interior. It can also compromise water shedding by creating pockets for water to pool. Finally, the flapping fabric can create disruptive noise or be more susceptible to wind damage. 

We developed a custom measurement technique for evaluating wet stretch in our fabrics that involves loading a strip of fabric in a nearly saturated humidity chamber and measuring the change in length. Figure 3 shows the wet stretch results for OSMO fabric compared to several pre-existing tent fabrics. On average, the OSMO fabrics have 3x less wet stretch than other tent fabrics. Translation? Your tent pitch stays tight, and you stay more comfortable. 

Reduced wet stretch is a result of the fabric staying dryer (see water repellency above) and the fabric’s unique construction properties. The polyester yarns in the OSMO weave absorb less water than nylon yarns, and less water absorption means less stretch (think of a dry sponge versus a wet sponge). 

 

Figure 3: Wet stretch results.

 

Hydrolysis Resistance 

Hydrolysis is the chemical breakdown of a compound due to water. In tent fabrics, water attacks the polyurethane coating responsible for making the fabric waterproof. A polyurethane coating that undergoes hydrolysis can be sticky, smelly, and flaky, degrading in performance and ultimately failing to be waterproof.  

Polyurethane candidates for the OSMO fabric were tested in the laboratory under three different hydrolysis-inducing environments which included hot water baths, hot sodium hydroxide solutions, and heat and humidity conditions in a controlled environment chamber. The extent of hydrolysis for conditioned polyurethane coatings was assessed using physical and analytical techniques. Through the combination of these methods, we were able to identify and select a proprietary coating with leading hydrolysis resistance among current tent coatings (Figure 4). 

The final result is that OSMO tent fabric is better at keeping you dry for longer than any other tent fabric we have ever tested. 

 

 

Tear Strength 

Not only do OSMO fabrics handle water extremely well, they also resist mechanical damage from tearing better than most available tent fabrics. The OSMO backpacking fabric, which weighs in at 48 grams per square meter (GSM) has a 69% increase in normalized tear strength (tear strength/area mass) compared to the average of tents of similar weight, making it one of the toughest fabrics used in a backpacking tent. 

 

 

The OSMO ultralight fabric is one of the lightest tent fabrics in the market, weighing only 29 GSM, and has a normalized tear strength 21% greater than the average of tent fabrics of a similar weight. Pound-for-pound, it is one of the toughest fabrics to make a tent from. 

The improvements in tear strength come from the high-tenacity nylon yarns in the composite weave. Yarn chemistry, yarn size, and weave structure were all considered and optimized to create the lightest weight and strongest fabric possible. 

 

Sustainability 

In developing OSMO, we were able to improve technical performance and reduce environmental impacts.  

OSMO fabrics use only recycled yarns. Using recycled yarns helps to prevent plastic pollution, keep fossil fuels in the ground, and reduce greenhouse gas emissions. Because of the composite nature of the fabric, only some of the yarns are dyed, which reduces the amount of dyestuff required by 25%–54%. Reduced dyestuffs equate to reduced energy consumption, greenhouse gas emissions, and waste chemicals. 

Most OSMO fabrics are certified as bluesign® approved. bluesign® approved textiles meet the strict safety and environmental requirements of bluesign®, an independent verifier of the environmental impacts of textiles. These articles are made from bluesign approved chemical products and raw materials and are produced in a resource-conserving way with a minimum impact on people and the environment. Qualifying for bluesign certification is an in-depth and lengthy process, but NEMO’s goal is to eventually have all OSMO fabrics meet bluesign® standards.  

OSMO fabrics are completely free of flame-retardant chemicals and fluorinated water repellents (PFAS). As part of the Outdoor Industry Association’s Chemicals Management Steering Committee and the Flame Retardant Cohort, NEMO has collaborated with other outdoor brands to remove these chemicals from supply chains. The FR- and PFAS-free OSMO fabrics are the first result of these efforts within our own product line. 

The purpose of sourcing materials with preferred attributes is to reduce the environmental impact of manufacturing, which was measured using the Higg Materials Sustainability Index (MSI). The MSI showed a greater than 50% reduction in chemical impact, a 5 kg CO2e reduction for every kg of OSMO fabric produced, and 21%–24% reduction in fossil fuel depletion when compared to a similar fabric without the environmental sustainability characteristics listed above. 

This work is not easy, but it is truly necessary. Climate change, chemical impacts, and resource depletion demand urgent action. OSMO fabrics represent a significant step forward in tent fabric sustainability, an advancement that is impactful on its own and serves as a template for future sustainability developments. 

 

Adventure 

OSMO fabrics embody how NEMO develops products. We strive to improve the experience of adventuring while protecting the people and places that make adventure possible. With OSMO, we’ve made a better tent fabric that, in turn, allows us to create a better tent experience. We also lowered the energy needed to produce the fabric and removed unwanted chemicals from the manufacturing process, improving the working conditions for our suppliers and reducing the impact on our planet. For these reasons, OSMO fabrics are our best tent fabrics yet. You can use them confidently on your next adventure knowing they will perform exceptionally and that they represent the right direction for a sustainable future.