Flexible packaging polyurethane laminating adhesive outdoor usage instructions

The conventional ordinary Polyurethane Adhesive laminated  packaging bags are not recommended for long-term outdoor use in the open air. They can only be temporarily stored in a shaded area. Customized products with weather-resistant formulas can be stored outdoors for a long time. 

 

The PU laminated rubber layers of ordinary flexible packaging are mostly of polyester-based systems, and their water resistance and UV resistance are relatively weak. The ultraviolet rays in outdoor sunlight continuously damage the molecular chains of the rubber layers, causing yellowing and a decrease in internal cohesion within a short period. In high-temperature environments combined with high humidity from rain and moisture, the polyester structure is prone to hydrolysis and softening, resulting in film delamination, gum detachment, and bag rupture. The temperature range of these conventional products is limited. Excessive summer sun exposure can cause the rubber layers to creep, while low-temperature frost can make the rubber membranes hard and brittle, cracking. The repeated expansion and contraction caused by temperature differences between day and night will accelerate the separation of the composite layers. 

If it is to be used outdoors, the polyether type weather-resistant polyurethane laminating adhesive needs to be replaced. The adhesive mixture should be compounded with UV absorbers and hydrolysis stabilizers. At the same time, the outer layer should use PE or BOPP weather-resistant base material that is added with UV-resistant masterbatch. The aluminum foil lamination type has better outdoor durability as the aluminum layer can block UV rays. 

 

Unmodified ordinary packaging bags can only be temporarily stored outdoors in a shady and rainproof area for a short period. When stored outdoors, they usually lose their effectiveness within 3 to 8 months. Customized weather-resistant models can achieve stable outdoor use for 1 to 3 years, meeting the outdoor packaging needs of agricultural supplies and industrial raw materials.