Gluing Ammonium-Salt-Treated Southern Pine with Resorcinol-Resin Adhesives

摘要

A comparison was made of the quality of bond produced by three commercial resorcinol-resin glues used on ammonium-salt-treated and untreated southern pine. The three adhesives were used on both the treated and the untreated specimens and had a postcuring period of 2 months before testing. The three adhesives, with two assembly times, 20 minutes and 60 minutes, and with two curing temperatures, 80F.and 150F., provided for 12 combinations of variables. The joints of the bonded-untreated southern pine had significantly greater shear strength and greater wood failure than the joints of the bonded-treated pine. The percentage of delamination was significantly lower in the glued specimens of untreated pine than in their treated counterparts. The ammonium-salt fire retardants appeared to react with the resorcinol-resin glues. Glue increased in viscosity more rapidly on surfaces of the treated wood than on the corresponding surfaces of the untreated wood. Less glue was squeezed from the gluelines of the treated specimens. The glues with liquid hardeners appeared to spread and wet the treated surfaces more readily. (Author)