An
emulsion comprising water as the continuous phase, a
wax as the discontinuous phase, an emulsifier and a
preservative having the general structure: wherein R1 can be a heterocycle containing
nitrogen and
sulfur, such as thiazolyl, isothiazolyl, or thiadiazolyl, which can optionally be substituted with C1-C6
alkyl; R2 can be
hydrogen or C1-C6
alkyl, specifically
hydrogen; n is 0, 1, 2, or 3; each instance of R3 can independently be
hydrogen, C1-C6
alkyl, phenoxy, C1-C6 alkoxy, halo, amino, C1-C6 alkylamino, di C1-C6 alkyl amino, imidazolyl, thiazolyl, isothiazolyl, thiadiazolyl, thienyl, furyl, pyrryl, naphthyl, phenyl, halophenyl, C1-C6 alkyl phenyl, or C1-C6 alkoxyphenyl. The
preservative may be added to the
emulsion after the
emulsion is formed. The emulsion can be incorporated into a
gypsum product such as
gypsum board or
gypsum wood
fiber board. The gypsum product may be made by forming a
slurry containing gypsum, water, and the emulsion into a
solid product. A method for improving the
water resistance of a lignocellulosic composite product prepared by mixing lignocellulosic material with a binder to form a mixture and solidifying the mixture in a selected configuration to form the composite product may include adding to the mixture an emulsion as described above.