Enhanced Poplar Lvl Production Process And Product Characteristics

LVL (Laminated Veneer Lumber, referred to as LVL) which has high strength, stable mechanical properties, flexible sizes features, is a new-construction composite materials of high performance and eco-environmental characteristics. In recent years, Chinese LVL was developing rapidly. Using fast-growing artificial wood veneer which had been modified manufacture high strength and beautiful texture enhanced laminated veneer lumber, which not only can be used efficiently our forest resources, but also the fast-growing wood products'added value improved greatly.This paper is based on the summary of predecessor's research on Poplar and LVL, to create an enhanced poplar LVL in accordance with the actual situation on the poplar wood veneer, and to conduct a series of studies on its physical properties and mechanical strength. This research use Poplar veneer as the main raw materials, use low molecular weight water-soluble PF and UF resin as dipping liquid, to manufacture intensified Poplar LVL. In the process of manufacturing intensified Poplar LVL, explore the best impregnation process, to establish the relationship between material properties and Process Factors by discussing the soaking time in the vacuum, the resin solid content, soaking temperature, soaking time at room temperature, and then identify the optimal process parameters. According to the conditions of production equipment and the product end-uses of the final performance requirements, recommending the best urea-formaldehyde resin impregnated technology parameters are:the soaking time in the vacuum is 30min,25%solid resin content, soaking temperature of 30-35℃, atmospheric pressure impregnation time is 3h; The best process parameters of PF resin impregnated production were:the soaking time in the vacuum is 30min,25%solid resin content, dipping temperature is 35-40℃, atmospheric pressure soaking time is 9h.Through the improvement of test methods, the results show that the physical mechanics properties of the specimen can completely meet the Japanese JAS standards FC1 laminated veneer lumber, Poplar LVL enhanced by PF resin can used indoor and outdoor decorative wooden structure requirements, UF Resin enhanced Poplar LVL reached interior non-structural decorative wood requirements.In addition, through infrared spectroscopy can find that there is not significant difference between the infrared spectra of soaking enhanced poplar LVL and the IR spectra of resins, and can know that the resin only filled mechanically in the poplar veneer compared to the resin's synthesis process; Through the electron microscope can found that the result of PF resin impregnated Poplar LVL is better than urea-formaldehyde resin impregnated. When resin immersed in poplar veneer, the main gap is immersed in wood from the cells inside, then followed by cell wall into the timber; at the same time, observed that the lateral permeability of the ducal cells is much worse than the tracheid cells.