There are many performance requirements for hot melt adhesive mesh films, and water resistance is one of them, which is also one of the more frequently mentioned properties. Especially for the clothing industry, the water washing resistance of hot melt adhesive mesh film is important, as it relates to the durability of clothing without seam bonding. Simply put, water resistance refers to the ability of a material (usually a fabric) to maintain high adhesive strength after being bonded with a hot melt adhesive mesh, soaked in water at a certain temperature, and repeatedly rubbed. The hot melt adhesive mesh films with good water washing resistance are TPU and PO hot melt adhesive mesh films. As they are often used in the clothing industry, there are usually certain requirements for the softness of the hot melt adhesive mesh film, so TPU hot melt adhesive film is more commonly used. In addition, the widely used EVA hot melt adhesive mesh film also has certain water washing resistance, but its effectiveness is not as good as TPU hot melt adhesive mesh film. The water washing resistance is also divided into different levels, such as room temperature washing, 60 ℃ washing, 90 ℃ washing, and so on. The higher the temperature, the higher the requirement for the water washing resistance of the hot melt adhesive mesh film. Taking TPU hot melt adhesive mesh film as an example, its resistance to normal temperature water washing is generally not a problem for most TPU hot melt adhesive mesh films, but for 60 ℃ water washing, not all TPUs can withstand it. Because for hot melt adhesive membranes, there is also a melting point issue. Many hot melt adhesive membranes may have an initial melting point lower than 60 ℃, and TPU hot melt adhesive membranes are no exception. So, when the water temperature reaches 60 ℃, the mesh of the bonding material has actually melted to a certain extent, so of course, it cannot withstand water washing. Therefore, the testing requirements for resistance to 90 ℃ water washing conditions are even more stringent. Most hot melt adhesive mesh films may not meet this requirement, and only a very small number of TPU hot melt adhesive mesh films can meet the conditions for resistance to 90 ℃ water washing. Special high-temperature resistant formulas are needed to meet this requirement.
