单板条织合层积板制造工艺及强度特性OA

Stitched strand board(SSB)is a novel engineered wood product,which is made by first processing veneer into modular long wood strips.These strips are then randomly reassembled into a layered wood curtain,followed by gluing,cross-lamination,and hot-pressing to form the final board.To improve the production efficiency of SSB and reduce the production cost to prepare engineered wood products with light weight and high strength,this study took domestic rubber wood veneer as raw material,compared the differences of temperature responses and physical and mechanical properties between SSB and plywood,and investigated the effects of different wood curtain gaps on the temperature rise and physical and mechanical properties of SSB.The results showed that:(1)During the hot-pressing of SSB,the temperature variation in the core layer was primarily divided into a rapid heating stage and a slow heating stage.In the rapid heating stage,the heat transfer efficiency of SSB was approximately 10.1%higher than that of plywood due to thermal convection effects induced by gaps in the wood veneer arrangement,which significantly reduced the conventional hot-pressing duration required for SSB.(2)The heating efficiency of SSB increased with increased gap ratios,however,during the subsequent slow heating stage,the temperature rise efficiency in the core layer of the mat decreased as the gap ratio increased.(3)While SSB exhibited comparable bending performance to plywood,it demonstrated lower density,higher strength to weight ratio and specific stiffness,along with reduced variability in bending properties.(4)As the average wood veneer gap ratio increased from 3%to 9%,gradual declines were observed in SSB density,adhesive shear strength,and bending performance.Comprehensive analysis indicated that SSB specimens fabricated with average wood veneer gap ratios ranging from 3%to 6%using domestic rubberwood exhibited a superior strength to weight ratio,enhanced specific stiffness,and improved homogeneity.All physical and mechanical properties met the requirements for the F27.0 grade as specified in the Chinese national standard GB/T 35216-2017"Structural plywood".