The lap-shear strength of bonds between Oriented Strand Board (OSB) like strands coated with pMDI resin

摘要

It is well known that resin is applied to wood strands as small discrete droplets during the manufacture of OSB. The quantity of resin applied is low and coverage of strands is incomplete. During pressing strands come into close proximity and bonding between strands may occur as a result of resin to wood contact, resin to resin contact, or a combination of the two. Strong bonds are routinely made during the manufacture of plywood where resin is applied to only one side of the veneer sheet and transferred to the adjacent veneer during pressing. For OSB it is not known which of the bond types produce stronger bonds: resin-to-wood or resin-to-resin contacts. This note investigated the bond strength of OSB-like lap-shear specimens in which pMDI-resin was applied to either one or both surfaces of the strands prior to pressing. Two resin levels were employed, 2 or 10%. The aim was to determine which bond type, resin-to-resin contact or resin-to-wood contact, results in higher bond strength between OSB strands.