Pengaruh Jenis Isolat Lignin Dan Nisbah Mol L/f Pada Perekat Lignin Formaldehida Terhadap Keteguhan Rekat Kayu Lapis Tusam *

It has been known that lignin can be used as plywood adhesive for exterior purpose. The sources of lignin are black liquor indulin-AT (commercial lignin).A study on lignin formaldehyde resin making from black liquor and indulin-AT was done and the results were used to predict the effect of lignin isolate type and L/F mole ratio on plywood bonding strength. The results show taht the type of lignin isolate and L/F mole ratio have highly significant effect on plywood bonding strength. The mole ratio L/F of 1 : 1.50 and 1:1.75 by lignin isolate from indulin-AT result in plywood bonding strength about 7.5 kg/cm2 and 8.8 kg/cm2, respectively. The bonding strength of these plywood conforms with the 1983 Japanese standard for exterior purpose