How to detect the quality of PVA membrane in cold water

Customer encountered in pva water soluble film to choose how to identify water soluble film product quality problems, Suggestions from the following several aspects to consider. 

 1) Water soluble: cold water soluble film requirements can dissolve in 4 ℃ above water. The faster the better. Dissolve the remaining residue after as little as possible. The water quality of the almost syllabic better after dissolving. 

 2) Appearance: winding as smooth as possible. The outer surface of the winding cannot have obvious concave and convex and wrinkles roll film two end as smooth as possible, requirements & plusmn; 2 mm or less. Membrane surface can not have defects such as bubbles, perforation, slag inclusion, black spots.

 3) Mechanical strength, tensile strength requirements in more than 25 mpa. Too easily pulled apart or cause drag mark. Elongation at break requirements in more than 180%. Less than is not soft. Rectangular tear resistance requirement at about 80 kn/m. Otherwise very brittle fracture. 

 4) Storage time: stable quality of the water soluble film deposit date can be in 1 - More than 2 years, In the case of not be affected with damp be affected with damp) .