Study On Preparation Of Flame Retardant Paper Using Mg-Al Hydrotalcites As Flame Retardant

In this paper, flame retardant paper was prepared by three different processes. The first method was adding flame retardant agents into furnish. The second method was coating flame retardant agents onto ordinary paper. The third method was coating flame retardant agents onto flame retardant base paper, where flame retardant base paper was prepared based on fiber loading technology using in situ synthesis of Mg-Al hydrotalcites in the lumen or cell wall of pulp fibers. All the three methods above were built on flame retardant system based on Mg-Al hydrotalcites. For the first two methods, flame retardant agents were combined effectively to finalize the best flame retardants system. As for the third method, the papermaking condition of flame retardant base paper was studied, in which the effect of different pulps ratio, beating degrees and dosages of filler on flame retardant properties of paper were extensively investigated.The results showed that the flame retardant properties of paper prepared by adding flame retardant agents into paper were poor, which couldn’t meet the requirements in the GB/T14656-2009.Flame retardant properties of paper prepared by the second method exhibited a good performance, which met the requirements in the GB/T14656-2009. Red phosphorus and APP (ammonium polyphosphate) both demonstrated obvious synergies with other flame retardant agents. Whereas in the Mg-Al hydrotalcites flame retardant system, Mg-Al hydrotalcites and APP didn’t exist a good synergy. However the performance of the red phosphorus was better than that of APP. Results suggested that the Mg-Al hydrotalcites and red phosphorus gave a good synergistic effect with the length of charring nearly50.9mm, afterflame time and afterglow time was about1.5s and4.1s, respectively, when the amount of Mg-Al hydrotalcites and red phosphorus were90phr (parts per hundreds of rubber) and10phr, respectively.Magnesium hydroxide and aluminum hydroxide were used to partial substitute for Mg-Al hydrotalcites as flame retardant agents, the results showed that flame retardant properties of paper decreased slightly, but still met the demands for flame retardant paper. When magnesium hydroxide and aluminum hydroxide substituted for40%Mg-Al hydrotalcites, paper exhibited good flame retardant properties with the length of charring nearly80.9mm, afterflame time and afterglow time was about3.1s and2.3s, respectively. With the increasing of the coating weight, flame retardant properties increased at first and then decreased. When the coating weight reached about43g/m2, paper had good flame retardant properties with the length of charring nearly50.9mm.Paper prepared by the third method had best flame retardant properties among the three methods. When the ratio of softwood bleached kraft pulp (SBKP) and bleached chemi-thermomechanical pulp (BCTMP) was3:7, beating degree of SBKP and BCTMP was45°SR and41°SR, dosage of filler was30%, paper had good flame retardant properties with the length of charring nearly40.3mm, afterflame time and afterglow time was about2.1s and2.2s, respectively.