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January 11, 2024 at 1:10:49 PM PST January 11, 2024 at 1:10:49 PM PSTth, January 11, 2024 at 1:10:49 PM PST

Many tests are involved with BOPP bags, the most common of which are drop, peel strength, and coefficient of friction (COF) tests. Some of these tests are simple, while others require specified machines dedicated to what standards need to be followed. All testing is important, and some customers have tighter tolerances require precise evaluations. 

Currently our BOPP testing is completed via our manufacturing partners, but Global-Pak is working to get machinery at our headquarters. We want to be able to verify testing at our facility and respond quickly to customers needs. Here is quick overview of the testing required for BOPP Bags: 

Drop Testing

A drop test is conducted when you fill the bag to the required weight, and then drop the bag from various heights.

Testing Procedure

Examples of drop testing include face drop, bottom drop, gusset drop 1, gusset drop 2, and corner drop. After each test, the bag is then checked for any damage to discover any structural issues with the bags or for areas of improvement. Random drops are exercised on more than one bag throughout the run, to ensure the bags have not lost any strength.

COF Testing

Our suppliers use the standard ASTM D1894 for measuring their kinetic (moving) and static (starting) resistance of one surface being dragged across another. The shorter version of this is a measurement of how slippery the bags are. The higher the COF on a bag, the better the grip. COF of less than 0.25 is considered low COF (High Slip), while COF greater than 0.45 is considered high COF (low/non-slip).

Testing Procedure

A specimen is attached to a sled of specified weight and the sled is pulled across a second surface at a speed of 150mm/minute. The force to get the sled started (static) and to maintain motion (kinetic) is measured. The specimen size needs to be a 64mm (2.5”) square, along with a 254mm x 127mm (10” x 5”) second surface. Both static and kinetic coefficient of friction can be calculated. The static coefficient of friction is equal to the initial force scale reading divided by the sled weight. The kinetic coefficient of friction is equal to the average force reading obtained during uniform sliding of the surfaces, divided by the sled weight. (All measurements are in grams.)

Peel Testing

Our suppliers use the standard ASTM D1876 to measure the adhesive bonds on the bag. This is to see if the bonds hold up under a certain amount of peel resistance by means of T-type specimen.

Testing Procedure

The specimen is cut at 1” wide and 12” long with 3” length on each side for gripping, and it is positioned on the machine to look like the letter “T” so it can be loaded for peeling. There are 10 specimens cut per adhesive, and all samples are conditioned in 23 degrees C with 50% humidity for 7 days. The conditions change depending on the customers’ needs and it is all dependent on what environment the bags will be exposed to (hotter, colder etc.) The test runs at 10 inches/min for 9 inches of travel. You will want to find the minimum, maximum, and average peel force between all the samples. This gives a better representation of the consistency of the bags and max amount pressure that can be applied to the bags before the adhesive starts to give.

When dealing with BOPP Bags, these are the 3 types of testing customers generally request. If you want more niche testing, we can send samples to a test house for measurements. If you have any questions on BOPP Bags, please don’t hesitate to ask your sales rep and we will certainly get you the answers you need.