Study On A Flame-Retard Mdf Made With App Complex Flame Retardant Of High Degree Polymerization

In this study, the APP of high degree polymerization was used as the main component of the flame retardant to make a flame-retard medium density fiberboard (MDF). The flame retardant also contained melamine, boric acid and M (a kind of high efficient expansion agent). The influence of the melamine, boric acid and M as coordinate agents on the properties of flame-retard MDF was discussed. The optimal composition of APP and the coordinate agents was obtained through a formulation design. Then hot-pressing process test was carried out according to the optimal flame retardant formulation, and the influence of the hot-pressing time, flame retardant amount and resin content on the physical mechanical properties and flame-retard performance of the flame-retard MDF was studied. Main results are as follows.The flame-retard performance of the coordinate agents:M> boric acid melamine; with the coordinate agent increasing, the flame-retard performance of the panel was constantly improved and its MOR, MOE and IB decreased gradually; both melamine and boric acid showed negative effect on resistance of water absorption and thickness swelling, while the effect of M was negligible.The optimal formulation of flame retardant was:APP68.5%, melamine6.2%, borate11.6%and M13.7%. When the addition amounts of the flame retardant and adhesives reached11%and15%respectively, the flame-retard performance of the panel could meet the B level of fire-prevention, and all the physical mechanical properties could meet the national standards.Flame retardant was the most critical factor for flame-retard performance, and its addition amount showed a very significant influence on the properties of the flame-retard MDF; with the flame retardant increasing, the mechanical strength of the flame-retard MDF decreased, and the water absorption and thickness swelling increased; the influence of flame retardant on MOR, IB and24h water absorption and thickness swelling was significant, while its influence on MOE was not.With the increase of the resin content, the mechanical strength of the panel was constantly improved, and the flame retard performance also improved to some extent; the influence of resin content on IB and24h water absorption and thickness swelling was significant, but no significant influence on MOR> MOE and the flame-retard performance.Increase of hot-pressing time was beneficial to IB. Hot-pressing showed no effect on the flame-retard performance, while its effect on the physical and mechanical properties went to some extent, but not significant.The importance order of the hot-pressing process factors was:resin content> the addition amount of the flame retardant> hot-pressing time; the optimum hot-pressing process was:the hot-pressing time6.5min, the addition amount of the flame retardant12%and resin content16%. By this technology, the flame-retard performance of the panel was better than B level of fire-prevention, and all the physical and mechanical properties were superior to the national standard.