Adhesive additives that are used in conjunction with polyisocyanate resins to form adhesive compositions. The adhesive additives contain castor oil, a mixture of castor oil and triglycerides, or a reaction product from the transesterification of one or more polyols and one or more triglycerides. The adhesive compositions are well suited for use as a binder in the manufacture of various composite products, particularly composite wood products including OSB construction panels and laminate composites.