Performance of Melamine Resin Adhesives in Various Exposures

Melamine-resin glue joints in laminated white oak, deteriorated progressively in salt-water soaking and had reached the stage of almost complete failure after 16 years. Melamine joints in laminated white oak, cured by high-frequency heating, performed as well as resorcinols and phenol resorcinols during 10 years of weather exposure. Melamine glue joints in laminated red oak showed slight weakening during 20 years of unheated storage. The strength of phenol-resorcinol glue joints remained about the same. Red oak beams glued with the two types of adhesives and exposed to the weather for about two decades were practically free of glue-joint delamination. Melamine glue joints in laminated Douglas- fir beams showed practically no delamination after about 20 years of exposure to the weather. In block-shear tests after about two decades of exposure, the wood failures were very high and essentially unchanged from initial tests; there was only a moderate reduction in shear strength over the same period. Similar performance was obtained with resorcinol and phenol-resorcinol glue joints, and no difference could be detected in glue-bond performance of the three glue types over the span of time involved. The one intermediate-temperature-setting melamine used in some of these studies gave generally poorer performance than the three high-temperature-setting melamines.

You must be logged in to download any documents. Please login (login accounts are free) or learn how to Become a Member