System for Spreading Small Amounts of Phenol-formaldehyde Resin Adhesive Using an Ink-jet Method I. Overview of the spreading system and effects of spreading rate on bonding properties

摘要

The objective of this study was to investigate the minimum spreading rate for sufficient bonding properties in wood based materials. A device for spreading small amounts was developed by modifying an ink-jet printer with a piezoelectric element. The device permitted the spread of about 5.0 cm(3)/m(2) (adhesive liquid base) of water-soluble phenol-formaldehyde resin (PF) adhesive uniformly onto the veneer. The relationships between adhesive spreading rate and bond properties were investigated using birch (Betula spp.) planed veneer and spreading the PF adhesive by the device. A spreading rate of 2.5 g/m(2) (solid base) of the PF adhesive per single glue line could achieve fully bonding strength with about 100% wood failure at normal conditions. In addition, bonded specimens with a spreading rate of over 7.7 g/m(2) (solid base) had full durability in a 72-hour continuous boiling test