Joining Techniques for a Nonwoven Wool Cover : A study on joining techniques for a thermally insulating non-woven wool cover for snow preservation

The preservation of snow and ice may seem unnecessary. However, as the global warming effects keep going in the wrong direction, it is becoming necessary to keep glaciers and alpine areas from melting and raising the ocean levels. A starting point is preserving snow at ski centres. Several initiatives have successfully pre-served snow at ski centres during the warmer off seasons by using thermally insulating textile covers, or glacier mats. The literature finds that these textile covers are almost always made of thermoplastic materials and work by keeping thermal energy and water from transporting between the layers and raising the temperature between the snow and the glacier mats. While the thermoplastic fibres have great insulation properties, the unsustainable production and, most importantly, their tendency to shed microplastics into the environment are a big environmental con-cern. Especially as microplastics are hard to remove and are not biodegradable. To combat this, The Loop Factory developed the snOWWOol glacier mat. It is a two-layered, waste wool and thermoplastic bi-component nonwoven sheet. The thermoplastic fibres are used to bond the wool fibres into a sheet while also addressing the main issue with the wool fibres and the glacier mats, the water resistance. Wool fibres have overlapping cuticle cell structure on the surface that repels water and dirt, but an inner cortex structure that tend to absorb moisture and water vapours, and a thermal calendaring of the surface of the glacier mats will increase the water repellence. The glacier mats are produced and transported in rolls and then prefer-ably joined on site. This puts restrictions and needs on the technique for joining them. Especially as the joints are generally the weakest point of a construction and where substances, like water and air tend to penetrate the easiest. This study aimed to explore and find the most promising joining technique for the glacier mats outer layer, along with how it affects the properties necessary for snow preservation. Some questions the study answers are, what are the needed properties of the covers to preserve snow, what techniques exist and are promising for joining the cover, and how do they affect the needed properties. Those properties were found to be ensuring a secure and tight seal, easy to attach and detach, how much water and air can penetrate the fabric, and how strong the joining is. Six techniques were found as promising and were tested and compared to a reference sample for water repellence, ease of attaching/detaching, seam rupture and air permeability. The result showed that the Arrow and Eye 1 (loose arrows) technique is the most promising for snow preservation, even though it did not perform as the best in all testing. Independent sample t-tests were performed on the Arrow and Eye 1 and the reference to see how they compared to each other. The results showed that the Arrow and Eye 1 performed worse in all categories besides air permeability. Overall, the Arow and Eye loose arrows is the technique to be explored further for joining the snOWWOol glacier mat.