Study On Lac Using In Wood Adhesive

The raw material of wood adhesive usually comes from the product of natural gas and petroleum. Moreover, the product using wood adhesive can emit formaldehyde.Today, the natural gas and petroleum are reducing, more and more attentions are paid to environment protection and resource conservation. So it has great significance to use renewable resource to produce wood adhesive. Lac is a natural polymer with atoxigenic, renewable, and naturally degradable characteristics. The study on lac using in wood adhesive is advantageous to the utilization of the renewable resource and environment protection. In additiong on, Lac resin is the main component in lac, and it is the mixture of hard resin and soft resin. The soft resin can synthesize the perfume. If the hard resin is not used, it can become waster. So the research on the application of hard resin is important.The paper studies the preparation of the modified PF with lac and hard resin. The cure time of the modified PF and the bond strength and emission of formaldehyde of the plywood bonded by this modified PF was measured in this paper. The results:1. In the lac resin, the content of hard resin is 65.1%, the content of soft resin is 28.2%. The IR analysis discovers that the component of lac and hard resin is almost alike. But, the DSC analysis discovers that the melting point of hard resin is higner than that of lac.2. The NH4OH, Na2CO3 and NH4HCO3 solution of lac are prepared. When their solid content are 20%, the solution have good stability.3. The NH4OH, Na2CO3 and NH4HCO3 solution of hard resin are prepared. When their solid content are 20%, the solution have good stability.4. The modification of PF resin with lac or hard resin is doable, their cure time is approaching to that of the general PF resin, the bond strength could meet the requirement of typeâ… plywood, the emission of the plywood was lower than that of general PF resin bonded ones.5. The IR analysis discovers the component of the modification of PF resin with hard resin and general PF resin is almost alike. the DSC analysis discovers that the modification of PF resin with hard resin cure faster than general PF.