Boiling water resistance, an important indicator of wood adhesives, represents the capability of adhesives for exterior woodwork applications. However, soy-based adhesives show poor behaviors in this respect, which limit their applications in outdoor environments. In this article, we report a synergistic modification method of integrating a cocrosslinking system of epoxied polyamideamine-epichlorohydrin (PAE) and organosilicon-acrylate copolymer latexes (OACLs) to improve soybean meal (SM)-based adhesive properties. Tailored PAE and OACL SM-based adhesives demonstrated robust crosslinking structures via multi-interfacial interactions, where PAE and OACL served as building blocks of an interpenetrating network, which was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy. The dry-shear strength, wet-shear strength, and boiling water strength of the resulting SM-based adhesives were 1.41 6 0.13, 1.32 6 0.17, and 1.20 6 0.11 MPa, respectively, with 15 wt % OACL loading; these were 41, 45, and 90% increases, respectively, over the SM-PAE adhesive with which we compared them. Most importantly, the excellent boiling water resistance of the adhesives make them practical for exterior plywood.Crosslinking is a particularly effective approach for enhancing adhesion properties. Currently, aldehydes, epoxy compounds, natural gellan, and genipin are the most commonly used crosslinkers to form intrapenetrating or interpenetrating networks with a soy-protein matrix. 3,4,17 When the crosslinked adhesive is used under humid conditions, the uniform and tough network limits the permeation of water molecules and, thus, improves the adhesion performance. For example, Li and coworkers 18,19 designed a series of soy protein-based adhesives consisting of a covalently crosslinked polyamideamine-epichlorohydrin (PAE) network and a physically crosslinked attapulgite or carboxylated styrene-butadiene rubber latex network between soy-protein matrixes. The boiling water strength of these adhesives ranged V C 2017 Wiley Periodicals, Inc.