Not all cooler bags are waterproof.
A cooler may use a waterproof lining material such as PEVA or TPU while the finished bag is only designed to be leak-resistant. The difference comes from the complete construction: how the liner is joined, whether seams penetrate the water-containing chamber, how the outer body is assembled, what closure is used, and what performance is verified on the finished product.
For custom cooler development, it is also important to clarify what “waterproof” is expected to mean. Keeping melted water from leaking out of the cooler and preventing water from entering into the cooler from outside are related, but they are not the same performance requirement.
Custom Cooler Bag Manufacturing Guide: Materials, Structure & Product DevelopmentA custom cooler bag does not follow one fixed three-layer formula. Its construction can combine a body material, optional foam insulation, an inner lining and different joining methods according to the intended use and
