Study On The Manufacturing Technique Of Wood-based Composite Panel Made From Waste MDF Fiber

The technique of various wood-based panels from waste MDF fiber was studied in this paper,which include the effect of pretretment for chemical charateristics of waste fiber MDF, the technique of fiberboards from waste fiber MDF, hydration of waste MDF fiber / cement and the technique of cement-fiber boards from waste fiber MDF(the technique of cement-waste MDF fiber boards), hydration of waste MDF fiber /gypsum and the technique of gypsum-fiber boards from waste fiber MDF(the technique of gypsum-waste MDF fiber boards). The results are as follows:(1)Pretreatment had significant impact for the waste MDF fibers.Measuring the pH, buffer capacity, UF curing time of waste fiber MDF after pretreatment,the results show that: Hot water is better,in the pretreatment of cold water, hot waterand 1% NaOH.(2)The technique of fiberboards from waste fiber MDF, the optimal process parameters: the mix fiber of length and short,density 0.65g/cm3, glue content of 15%, pressing temperature of 120℃,pressing time of 5min,and unit pressure is 3.0 Mpa.The performance of fiberboards were reached the national standard of MDF fiberboards GB/T11718-1999:MOR is 22.53Mpa,MOE is 2426.89 Mpa, IB is 0.85Mpa and 24hTS is8.19%.(3)Hydration test of waste MDF fiber-cement, results show that: chemical additives of CaC12 could largely improve the compatibility of cement and improve the maximum hydration temperature of mixture(waste MDF fiber-cement), addition 3% of CaCl2 by weight of cement is most appropriate; the optimal process parameters from the technique of cement-fiber board were that: density is 1.2g/cm3,fiber/cement ratio is 0.2,water/cement ratio is 0.4, CaC12 is 3%( weight of cement) and unit pressure is 2.5 Mpa,were reached the national standard of cement woodboards JC411-2007:MOR is 11.57MPa, soaking 24hMOR is 9.34 Mpa, MOE is 3172.90 Mpa, 24hTS is 0.95%.(4)Hydration test of waste MDF fiber-gypsum, results show that: Citric acid(CA)has significantly retardation effect for the hydration of gypsun, addition 3% of CaCl2 is better by weight of gypsum; The hydration curve of waste MDF fiber treated by hot water is closest to the hydration curve of pure gypsum,in the pretreatment of cold water, hot water and 1% NaOH; the optimal process parameters from the technique of gypsum-fiber board were that: density is 1.3g/cm3,fiber/ gypsum ratio is 0.2,water/ gypsum ratio is 0.35, CA is 0.01%( weight of gypsum) and unit pressure is 3.0 Mpa,were reached the national standard of LY/T1598-2002:MOR is 5.92MPa, MOE is 2420.37 Mpa,IB is 0.37 Mpa,24hTS is 1.21%.