Glue Application and Hot-pressing Technology of Parallel Strand Lumber

Parallel strand lumber(PSL) was manufactured from the waste poplar veneer strips,a by product from plywood enterprises.The influences 3 glue application methods,time of hot pressing and temperature on the physical and mechanical properties of PSL were investigated by analyzing the impacts of size of the strips,glue concentration and application time on the amount of glue-absorbing of each strip.Hot pressing technology was optimized.The results showed that the size of the veneer strands had no notable influence on the glue-absorbing amount,and it mainly affected the homogeneity and appearance quality of the product.The glue concentration is the main factor to affect the glue-absorbing amount of veneer strands,and in this study,PF resin with a concentration of 30% was selected.The glue-applying way was the main factor to affect the mechanical property of PSL.The hot-pressing time and temperature had significant influence on physical and mechanical properties of PSL.Considering physical and mechanical properties and homogeneity of product comprehensively,it was concluded that PSL with satisfactory quality would be manufactured by adopting the following conditions: length of veneer strands: 100 mm,glue application way: spraying;time of hot pressing: 35 min;temperature of hot pressing: 150 ℃.