Two-component solventless adhesive compositions

Abstract

Two-component solventless polyurethane adhesive compositions comprising an isocyanate component and an isocyanate-reactive component are disclosed, the compositions comprising an isocyanate component comprising an isocyanate-terminated prepolymer, and an isocyanate-reactive component comprising a polyether polyol, a phosphate ester adhesion promoter, and, a bio-based polyol. Methods for forming laminate structures are also disclosed, the methods comprising forming an adhesive composition by mixing an isocyanate adhesive component comprising an isocyanate-terminated prepolymer and an isocyanate-reactive adhesive component comprising a polyether polyol, a phosphate ester adhesion promoter, and a bio-based polyol, applying the adhesive composition to a surface of a first substrate, and bringing a surface of a second substrate into contact with the adhesive composition on the surface of the first substrate, thereby forming the laminate structure. Laminate structures are also disclosed.

Description

REFERENCE TO RELATED APPLICATIONS[0001]The present application claims the benefit of U.S. Provisional Application No. 62 / 516,916, filed on Jun. 8, 2017 and U.S. Provisional Application No. 62 / 512,208, filed on May 30, 2017.FIELD OF THE DISCLOSURE[0002]The instant disclosure relates to solventless adhesive compositions. More particularly, the disclosure relates to two-component solventless polyurethane adhesive compositions for use in laminated structures. The disclosed adhesive compositions comprise an isocyanate component comprising an isocyanate-terminated prepolymer, and an isocyanate-reactive component comprising a polyether polyol, a phosphate ester adhesion promoter, and, a bio-based polyol. The disclosed adhesive compositions exhibit improved properties over current solventless adhesive systems, for example—faster curing than current systems, quicker primary aromatic amine (“PAA”) decay, better adhesion to metalized films, and so on.[0003]The instant disclosure further relate...

AI Technical Summary

Benefits of technology

The patent text describes a new two-component solventless polyurethane-based adhesive composition that improves bond strength, curing speed, and metalized film adhesion. The adhesive includes an isocyanate component and an isocyanate-reactive component that react to form a cross-linked polymer network. The adhesive can be used in a variety of laminate structures, such as metalized films and polyester / polyolefin films commonly used in packaging applications. The patent also describes how the adhesive balances curing and pot-life properties by adjusting the reaction rate between the isocyanate component and the adhesive. Overall, the adhesive composition described in the patent provides faster curing, better metalized film adhesion, and improved chemical and thermal resistance compared to existing solventless adhesives.

Problems solved by technology

Solvent and water-based laminating adhesives are limited by the rate at which the solvent or water can be effectively dried and removed from the laminate structure after application of the adhesive.

However, solventless adhesives often encounter issues such as slow bond development, slow primary aromatic amine (“PAA”) decay, low adhesion to metal surfaces, ink smearing, and poor chemical and thermal resistance, particularly its use in more demanding applications.

Slow curing speed results in lower conversion efficiency.

Two-component solventless laminating adhesives, compared to traditional solvent-containing adhesives, exhibit weak initial bonds and longer time needs to be waited for slitting.