A Soybean Oil‐Based Adhesive and Its Application for Birdseed Binding

Abstract

AbstractCurrent birdseed binders are mainly based on animal protein and fat. However, exporting the seed cakes containing animal products to European countries can be difficult due to their import policies. A plant oil‐based adhesive may be capable of binding loose seeds together, enabling it to be used as an alternative to the animal protein‐based and fat‐based binders used currently and making the exportation possible. A soybean oil‐based adhesive was, therefore, synthesized and tested for birdseed binding in this study. The effects of the quantity of saturated fatty acylglycerols (i.e., fully hydrogenated soybean oil, FHSO) introduced into epoxidized soybean oil (ESO) and a phosphoric acid (H3PO4) cross‐linker on product characteristics were investigated. Increased quantity of FHSO improved the glass transition point (T g), hardness, and adhesion while further increasing the quantity led to various degrees of phase separation of the product. Increased quantity of H3PO4 also improved hardness and adhesion of the binder. A binder‐MDAG (a mixture of mono and diacylglycerols at about a 1:1 ratio as a hardening agent) mixture (BMD) having an average hardness and adhesion of 4024 and 1197 g, respectively, was selected for seed binding. Seed cakes bound with 15 wt.% BMD were about twice as hard as gelatin‐bound ones. Storage of the BMD itself in open air led to increased hardness, adhesion, and melting point, and storage of the seed cakes bound by BMD in open air led to increased hardness and high temperature tolerance. Seed cakes bound with BMD also presented much better water resistance.