You may see a list of different technical words being tossed around about the materials used in a backpack while you are going through our reviews or testing the right backpacks yourself. Questions tend to cross your mind, like what are the advantages and disadvantages of polyester and nylon? What does denier mean? Which material does a waterproof backpack use?
Don’t worry, we were also there. But here’s a summary of all the various terms, nomenclature, and technologies that the current backpacks use, and also the old school ones.
Nylon is one of the most common materials used in backpacks today and is widely used. In reality, a wide variety of plastics (polyamides) can be melted down and processed into different products, like fibers. It is these fibers that are woven for backpacks. One of the reasons why Nylon is so common for backpacks, apart from being able to be woven, is that it is sturdy, resilient and can withstand abrasion and temperatures very well. You will also be surprised to hear those typical backpack problems such as mold can be avoided, which is just another reason why you see it used almost everywhere. Travel backpacks are usually made of nylon.
Polyester is currently the most widely used cloth in the post-cotton era, aside from nylon. Polyester is also known as packcloth, which is inexpensive and keeps the colors well. This makes it the fabric of choice for school bags, especially for younger kid’s backpacks. Polyester backpacks are not as durable as their nylon or canvas counterparts, in accordance with the old saying that you get what you pay for. Therefore, lower end and inexpensive backpacks are mostly made of polyester, while nylon is the most costly option.
A really old fashioned material that reminds you of your parents’ backpacks they used to carry. Despite this, more trendy brands such as Hershel have made a comeback, as well as other brands where weight is not so much of a challenge. Originally, canvas was still made of cotton, and as a result, it was always heavy. It can be made from a number of fabrics these days and could be a little lighter. Usually, it’s still pretty strong, but it’s robust and typically lasts for a long time. You may be interested in our guide on the best canvas backpacks.
PP is a thermoplastic polymer formed by the neighboring monomers of propylene (ergo-poly-propylene). PP is a plastic that is very commonly used, and you’ll find it in everything from cords, to carpets, to paper. Those plastic pipette tips are made of PP, if you’ve ever been in a wet lab at school. Water is not absorbed by polypropylene and dries quickly; it is more hydrophobic than polyester. It’s a strong insulator as it doesn’t efficiently transfer heat. It’s made its way into backpacks, as such. You typically see tote bags or drawstring bags made of PP, but there are also parts made from certain backpacks.
Cordura fabrics are used for consumer goods requiring toughness, abrasion resistance and strength fabrics, tactical and military backpacks are some styles that use this material. When you see backpacks that are made of Cordura nylon or Cordura blends, a luxury brand name cloth is used. In higher-end packs, you’ll usually find Cordura nylon.
At similar intervals, Rip-stop nylon adds a grid of thicker threads sewn directly into the nylon. If the nylon is punctured, this eliminates the problem of tearing or unraveling and also allows waterproofing. However, if rip-stop is used in light fabrics, frequent usage will cause holes to open faster along the seams than in other thicker fabrics because lighter threads and thicker ripstop threads wear at differing speeds.
It is actually a piece of woven nylon fabric with a very special weave that makes it more rigid and resistant to wear than regular nylon. The traditional weave is 2×2, meaning two yarns of thread are spun instead of one in either direction. However, there are plenty of versions around. The original was still a 1050D product, but things have changed again and on the market, you can find a lot of variation. The only thing to bear in mind is that you know it is a really wear-resistant material that will last for a long time when Ballistic Nylon is used. Tumi Backpacks are a great example that uses this type of nylon.
Kodra was developed as an alternative to Cordura and originally came from a Korean manufacturer (Kolon International) with a long history of nylon-based fabrics going back to the 1950s. Kodra seems to be manufactured mostly by a number of Asian producers these days, so it is not as closely regulated as Cordura. However, much like Cordura, it is known to be very resistant to abrasion.
PVC fabric is sturdy and bright and can be used with all manner of items including workwear. It can also be used for applying color and waterproofing to backpacks.
DWR – Durable Water Repellent
Perhaps the most commonly used when it comes to waterproofing. DWR is a substance that is applied to help keep water at bay on the exterior of backpacks. Check out our guide on the best waterproof backpacks for travel.
PU/TPU (polyurethane/thermoplastic polyurethane)
The PU coatings/laminates provide the fabric with waterproofing. Around the exterior of the product, this adhesive is applied and is often found in tents and clothes.
Denier is a metric used to define what thickness or density basically is. It was originally meant to quantify different sizes of silk threads and is the weight of a strand of thread in grams of 9,000 meters, but it is theoretically not right to call it density, which is mass per unit volume. And the best kind of right is the scientifically sound one. Anytime you see a 500D nylon or 1000D polyester backpack, that means that that fabric weights 500 grams and 1000 grams. The higher the denier is, the better the material.
Thread Count (T)
Thread Count is an alternative to Denier when it comes to calculating fabric weight, not only as frequently found in the high-end backpack world, but still seen for fabrics in general. It is a count of how many threads a square inch has. Again, in general, a higher number implies a better material.
Grams per Square (GSM)
Based on the mass metric scale-grams per square meter (which in Imperial will be more like ounces per square inch). With polypropylene and other fabrics where no weaving is used is where it is most commonly seen, so thread weight or thread count is not as significant.
Stitches per inch are determined and requires a better balance. Backpacks usually have about 6-10 stitches per inch. Less than 6, and it tends to lack strong intensity in the bag. Conversely, heading above 10 will cause the strength to weaken when the threads are disturb the structural stability is lost. This is important for areas of load bearing, such as where the shoulder straps are attached to the backpack’s structure.
As far as fabrics are concerned, tenacity is how much the fabric prevents further tearing after a tear has began. Measures of grams per denier are included. Normally, nylon has greater tenacity than polyester. Two major varieties of nylon are available – 6 and 66. In backpacks, Nylon 66 is thicker but rarely used.
By making the fabric threads interlocked perpendicularly to create a link between the warp and weft lines, fabrics that are woven have greater strength. Woven garments, if not constructed of elastic fibers, do not spread in the direction of the warp and weft.
Through chemical , mechanical, or thermal procedures, non-woven fabrics are bound together. Felt, which is not spun or knitted together, is a typical example. Nonwoven fabrics are not as strong as woven fabrics, and to increase strength, they require an increase in density.