(440g) EDTA Modified Polyol Polymers for Performance Improvement of Laminating Adhesives

Laminating adhesives are widely used in manufacturing flexible laminates for food packaging applications. Based on the adhesive compositions, lamination adhesives can be classified into three categories: solventborne (SB), solventless (SL) and waterborne (WB). In recent years, solventless adhesives are the preferred choice for food packaging industry due to the benefits that they can offer: energy saving without either organic solvents or an aqueous carrier during the drying step, applied 100% solid that enable running the application process at high speed to save operational cost and increase productivity, and EH&S benefits due to removal of volatile organic solvent from the adhesive package.

However, SL laminating adhesive is mainly used for general performance application. Recently, silanes and phosphate adhesive promoters have been developed and used to upgrade the SL adhesive performance so the technology can be used for medium high performance packaging application, such as for packaging liquid food and aggressive food. However, silane based adhesion promoter results in potential pot life and shelf life issues due to the moisture sensitivity as well as food regulatory compliance risks; phosphate based adhesion promoter potentially has material shelf life concern.

In this work, we developed a new adhesion promoter technology based on EDTA dianhydride, which is used to modify the polyols coreactant. The generated EDTA-polyol polymer is used as adhesion promoter and applied to the solventless lamination system. The metalized film or foil adhesion and product resistance are significantly improved. Such inventive technology can upgrade the adhesive products from general performance to medium high performance application. US patents have been filed.