What is the reason for the spots and bubbles on the cover of plastic bags?
Jul 20, 2022
Spots and bubbles on the cover of plastic bags means that the sealing surface is not flat. The reasons are as follows:
1. Cause
①When heat sealing is performed on a hygroscopic material structure such as nylon film, the hygroscopic film absorbs moisture and generates air bubbles.
②The heat sealing knife or the heat sealing silicone pad is not flat.
③Insufficient heat sealing pressure.
④ Use one-component adhesives, such as neoprene adhesives, when heat sealing bags. Hot covers are prone to bumpy craters.
2. Solution
① Properly store raw materials and semi-finished products to avoid moisture absorption.
②Check or adjust the heat sealing knife and heat sealing silicone pad.
③ Replace the adhesive.
