Abstract
Halogen-containing flame-retardant paper products have both good efficacies and cost competitiveness. However, facing increasingly stringent environmental protection and safety requirements, these products could become a liability in service. Developing effective and cost-competitive non-halogen flame retardant paper products has thus become a goal of product development by the paper industry. In this study, we investigated the application of certain papermaking functional additives, particularly minerals, to develop fire resistant agents or flame-retardant papers that are not liable to become soggy when exposed to moisture in the atmosphere. Five inorganic pigments (calcium carbonate, kaolin clay, magnesium hydroxide, aluminum hydroxide, and sericite mica) and a swelling-type flame-retardant (a phosphor-nitrogen (P-N) organic compound) were examined. We applied the minerals either by internal addition to a pulp furnish and formation into base sheets, or by surface coating applied to commercial copy paper substrates, and finally by adding the minerals at different proportions internally to the pulp furnish and then surface coating with the P-N compound. The prepared sheets were tested for their flame-retardation performance. Service environment-simulated treatments were also conducted on the papers to observe changes in their mechanical properties, so as to find the optimal flame retarding filler ratios and coating amount formulations. The economic efficiencies of the various formulations were also analyzed to serve as a database for research and industrial reference. In total, 5 blended formulas allowed the papers to attain a class I flame-retardation rating. After the degradation test and economic analysis, we deemed that aluminum hydroxide and magnesium hydroxide were too expensive, and were liable to lose their fire-resistance after degradation. Sericite mica-treated paper showed lower strength losses after degradation treatment; however, the fire rating decreased to class III. Calcium carbonate- and kaolin clay-based papers had reduced fire ratings to class II after degradation.