The first is for the fabric itself. Throughout the development history of waterproof fabrics, they have experienced compact fabrics (such as 210D nylon-1000D nylon, etc.), PU coating, PV coating (also called PVC coating), and pure natural wax ( Greenland Wax) coating is now dominated by film-type fabrics. The key to playing a waterproof role lies in the waterproof film in the fabric.
At the beginning of the invention of waterproof film, the most used PTFE (polytetrafluoroethylene) membrane was a kind of microporous membrane. So a non-porous PVC (polyvinyl chloride) film appeared, which can effectively waterproof. However, studies have shown that PVC film pollutes the atmosphere and land during manufacturing, landfill and incineration, and therefore encounters resistance from the environmental protection community.
In 1980, Sympatex, a German high-tech fabric manufacturer, independently developed an environmentally friendly film ---TPU film, which does not contain PVC or PTFE components, is harmless to the human body, and can be recycled. However, the membrane developed by Sympatex considers waterproof and breathability, and the thickness is only 0.01mm, which cannot achieve waterproof and impermeable effects.
The United States LONGHIKER, the world's first outdoor waterproof bag concept, established a waterproof fabric technology research center in Taiwan in 2004 and developed a 100% waterproof Waterlock film (also a TPU film) with a thickness of up to 0.2mm.
These films with the strongest waterproof technology combine the film with nylon, polyester and other fabrics to form a film-coated fabric through a film-coating process. Backpack manufacturers can directly purchase the film-coated fabric to make backpack products.
Water-repellent fabrics are commonly found on backpacks in the following categories:
1. Compact fabrics, such as 210DD nylon-1000D nylon. It is still widely used in many high-end backpacks such as Osprey, GREGORY, Bigpack (using CORDURA fabric, which is also a kind of nylon) and other high-end backpacks. The reason is that they have anti-tear properties and have certain water repellent properties.
2. Pure natural wax (Greenland Wax) coated fabrics, such as Fjallraven G1000 fabric was exclusively developed by the Swedish Arctic Fox in 1968. It is made of long-fiber cotton blended fibers without any chemical coating, but is applied on the surface of the fabric. A pure natural wax (Greenland Wax) to achieve excellent water repellent performance.
3. DWR coated fabric, on the surface of waterproof backpack fabric pasted with PTFE microporous membrane and Sympatex breathable membrane. We can see that the water will gather into small water droplets and then slide down. This is when DWR (Durable Water Repellency) is added when the fabric is shaped, so that the water that drips on the surface of the fabric gathers to form small water droplets or slides directly from the surface to prevent the fabric from absorbing water. .
A waterproof bag made of water-repellent fabric is water-repellent.
Fully waterproof fabrics are commonly found on backpacks in the following categories:
1. PVC clip net materials, such as PVC500D clip net, PVC600D clip net, PVC1000D clip. The waterproof bags produced by British Overboard and American Sealline basically use this kind of fabric.
2. Nylon TPU laminated fabrics, such as 210D nylon TPU, 420D nylon TPU, waterproof bags produced by LONGHIKER in the United States, and Arcteryx in Canada by Watershed, many of which use this type of fabric.
However, the full waterproofness of the fabric does not mean that the product is also fully waterproof. If the fully waterproof fabric uses traditional stitching seams and zipper closures, the stitches and zipper gaps at the seams cannot reach 100% waterproofness. Can only be defined as water repellent.
How to achieve full waterproof backpack?
First of all, fully waterproof fabrics should be used. Secondly, the seams of the fabrics should be seamlessly welded. Finally, the zipper should be replaced by a roll-up method or a fully waterproof and airtight zipper. Because it is difficult to make fully waterproof fabrics, the hot-melt welding technology is still not popularized in the hands of a few manufacturers, and it is a scarce commodity.
With the continuous improvement of living standards, it is believed that more and more outdoor enthusiasts will recognize and choose fully waterproof hiking backpacks.