Posted 19 July 2011
The backpack is the most important supply of the return of classes. And it is also the most expensive. So, when choosing from all the backpacks, it is sometimes difficult to decide for the one that will accompany you next for the whole year.
Here is some information that will be useful for you to estimate the quality of a backpack at the time of the fateful choice.
What does the quality of a backpack depend on?
The backpack is essential in our daily life whether it is for school, leisure, professional use.. but the quality of a backpack remains mysterious...5 main criteria, fabric, coating, zippers, Assembly and toxicity of materials, determine the quality of a backpack.
In the store you can observe in the first place the nature of the fabric: polyester (the bulk of back-to-school backpacks), polyamide, cordura... But, it's mostly its titration, the size of the yarn, expressed in denier (D), which affects the quality of the fabric of a bag. A backpack is therefore always characterized by 2 numbers corresponding to the titration in chain and frame as 600/600 denier or 600/300 denier (because the titration in chain and frame can be quite different. Of course, the higher the titration, the denser the fabric and therefore the resistant backpack: a 600/600 d fabric is heavier and therefore more qualitative than a 600/300d fabric.
When you walk around the back-to-school radius, you can observe, depending on the signs and marks, that some backpacks bear the mention of a 600D or 300D titration. These data are therefore incomplete since it lacks the 2nd titration of the fabric to estimate its quality. So you do not have to rely on this number alone to make your choice because you do not have the 2nd digit which can be 300D or 600D which will be more solid.
The number of wires is also very important for estimating the quality of a fabric. Let's take a concrete example: a 600/600 d fabric with a small number of threads can resemble a mop while the same fabric with a large number of threads will be denser and more resistant.
The photo below illustrates this well.
Associated with the titration of the fabric, the number of threads per centimeter makes it possible to determine the weight of the fabric and thus assess its quality. The average weight of school backpack fabrics is 140g.
The fabrics used by Bodypack are of high density since there are 31 threads per centimeter (21 threads in chain and 10 in weft) while the market average, especially in school, is at 24 threads.
Coating is the process of treatment of the hidden face of the fabric to make it more durable and waterproof. The technique of coating used (glued, pressed or sprayed against the fabric) as well as material coat therefore also affect the quality of the backpack.
For example, a basic coating, PVC, will assemble a PVC sheet with the fabric through a sheet of glue between the two. By adding an extra sheet to the fabric, this coating will give a cardboard effect to the fabric and makes it heavier; this suggests to consumers that the fabric is resistant because thicker and stiffer.
While a polyurethane (PU) coating, a technique used on mountain backpacks, is more resistant by its process. Unlike PVC coating, the polyurethane liquid is sprayed on the fabric to completely impregnate it. This technique requires a large yarn density so that the polyurethane spray does not pass through the fabric. It allows a better connection between the fibers of the fabric and the coating.
This coating is therefore almost invisible and allows to have a softer and lighter fabric.
Contrary to what can be imagined in stores facing all backpacks, the cardboard effect of a fabric or the weight of the bag is often the guarantee of a lower quality. Like the bodypack backpacks, a dense and therefore solid fabric is coated with polyurethane which gives it a great lightness.
Often, it is they who give in with wear and tear. Their quality depends on their manufacture(are they from recognized suppliers of zippers like YKK or SBS?) and thickness. The wider the closure, the stronger it is.
In stores, you can abuse the slider a little and use the zipper several times in a row, for those of poor quality it feels already when testing. A slider that twists between your fingers is synonymous with a poor-quality closure.
Mounting the backpack
The construction of the backpack participates in its resistance over time, the more anchor points to distribute the weight, the more the bag will withstand the weight of school supplies. Thus, a wide shoulder strap will more easily withstand the load of the bag than a thin shoulder strap. Similarly, bartacks, slanting seams to prevent the fabric from sagging, on straps or tension points contribute to the strength of the bag.
"Phthalate-free" is beginning to appear on products such as children's toys, shower gels and recently backpacks. The absence of toxic materials such as phthalates or other PVC, cadmium, azoic dye, is also to be taken into account when choosing it.
It is not automatic on all backpacks, so it is important when it is present. Because the bags are subjected to severe strain and can be forced to yield.