When you are looking for a banner material surely the weight of the material is a clear and easy guide to what is the best quality? 510 grams is more than 440 so it must be better. Unfortunately, the market is no longer that simple and weight can be a red herring when it comes to run ability, durability and machine and ink compatibility.
The coating of a banner material is there to give you an attractive look and feel, but it is also there to hide what is inside, or what isn’t. To understand what you are buying and if it will be suitable for the task at hand you have to understand what lies beneath the coating. Much like people, or a jam sandwich, the important stuff is on the inside.
Banner material products, be they Frontlit, Backlit, Blockout or Mesh need a foundation to be built on. One of the most important parts of any material is the scrim or base cloth. This is where the term scrim banner comes from, essentially meaning a material with a supporting internal cloth that makes the material suitable for external use.
This base cloth is typically made from high tenacity polyester yarn and PVC is applied to this via various means to create a finished printable product. Mostly obscured from view the base cloth is often over looked when making buying decisions. This is a pity as it is ultimately responsible for attributes in the finished material such as tear and tensile strength, as well as having a roll to play in the look and feel of the surface of the material.
Let’s start with some weaving terminology (sorry, but we need to do this). Warp and weft are terms for the two basic components used in weaving to turn thread or yarn into fabric. The lengthwise or longitudinal warp yarns are held stationary in tension on a frame or loom while the transverse weft is drawn through and inserted over-and-under the warp. The easy way to remember this is “weft goes right to left”.
Denier is a term used to measure the thickness of threads. It’s a measure of linear mass density of fibres, however a practical explanation would be a 500-denier thread means that the thread contains 500 twists in the finished length. The higher the number the thicker the thread and the stronger it is (if it is made of the same fibres). For banner, the denier numbers are shown in warp and weft directions. 250 x 500 means the warp threads are 250 denier and the weft threads are 500 denier.
The next consideration is the layout or pattern of the weaving. More threads per inch help make a PVC banner smoother and stronger. For PVC banner, the numbers are shown in warp and weft directions. 18 x 12 means there are 12 threads in an inch across the warp direction, and 18 threads in an inch across the weft direction.
For these reasons a 1000 x 1000, 18 x 18 material will be stronger and smoother than a 500 x 500, 9 x 9 due to the higher denier and more complicated weaving. This is also the reason that a 300 x 500 material with a balanced thread count will tear more easily in one direction that the other. A smooth banner creates an attractive print surface, but a strong banner stays where you put it. A small banner made from a strong material can also be finished without a hem, saving on production time and materials.
Base cloth becomes even more important when making large banners. A higher thread count allows force to be spread across a material, distributing gusts of wind more evenly. The strong foundation found with better base cloth also improves the materials resistance to heat during the printing process and promotes easier feeding of material at speed.
Base cloth can also be made from knitted polyester as opposed to woven yarn. Knitted polyester is not as strong as woven polyester and therefore tends to be used in more economical products. The higher amount of yarn in a woven material and its denser construction make for a stronger and more dimensionally stable fabric.
A material with a low denier, simple knitted base cloth but a heavy total material weight will be easy to tear by hand. Whereas a material with a lower finished coated weight but a woven, high thread count base cloth, made from high denier yarn will be many times stronger.
It is for this reason you can buy a 510g material that tears under very little load but a 440g product that is much stronger. It is important to choose your material based on the sum of it’s parts and not just on the total weight of the material. More does not necessarily mean better.
There are plenty of products on the market which have deceptively high material weights and very smooth surfaces. This has been achieved by having a very simple, low denier, knitted base cloth hidden under a thick layer of PVC. Its easy to spot these products once you know what to look for.
Check the specification sheet for the facts about the base cloth, or to do a quick on the spot test just try to tear the material with your hands. I can tear a 300 x 500, 18 x 12 material easily, if you can tear a 1000 x 1000, 18 x 18 I hope we never meet on bad terms.