A lignocellulosic product comprises a plurality of lignocellulosic pieces, and an isocyanate component and a processing aid disposed on the pieces. The processing aid is reactive with the isocyanate component, comprises a graft polyol having a continuous and discontinuous phase, and can be used to form a lignocellulosic composite article. The processing aid is useful for imparting the composite article with moisture resistance, swelling resistance, and toughness, as well as providing cold-tack during manufacture of the composite article from the product. The continuous phase comprises an isocyanate-reactive component. The discontinuous phase comprises polymeric particles. The isocyanate component and the processing aid are present in the product a combined amount of from about (1) to about (25) parts by weight based on (100) parts by weight of the product. The composite article can be various engineered lignocellulosic composites, such as oriented strand board (OSB), particleboard (PB), scrimber, or fiberboard.