| abstract |
A binder has at least one isocyanate and at least one biopolymer mixed with water. The biopolymer may be a biopolymer nanoparticle or cooked and chemically modified starch. Optionally, the binder may also include urea. The biopolymer and water are mixed, and the isocyanate is added to the mixture. The binder may have a viscosity that is suitable for being sprayed on a substrate to make a composite material, for example a viscosity of 700 cP or less or 500 cP or less at 40° C. The substrate may be wood, another lignocellulosic material, or synthetic or natural fibers. In particular examples, the binder is used to make no added formaldehyde wood composites including particle board and fiberboard. Alternatively, the binder may have a higher viscosity and be used to make plywood. |