耐燃合板製造及其耐燃效應（I）表面燃燒性

Red lauan and radiata pine veneers were used as raw materials, soaked with eleven chemical mixtures, at 10% concentration to screen out potential fire retardants by oxygen index (OI) method. Three screened mixtures (designated as D, G, and I) of higher OI, together with CNS Type C (designated as C) were impregnated into veneers to produce 10mm thick fire-retardant plywood. The spread amount of melamine-urea-formaldehyde (MUF) adhesives varied from 161.5 to 204.5 g/m^2 during manufacturing. A 3rd grade incombustibility national standard was used as a criterion to test the combustibility and fire-retardancy improvement of each treatment. The flame inhibition parameter for the selected D, G, I and C mixtures were 0.98, 0.98, 0.95, and 0.94 respectively for red lauan, and 1.21, 1.18, 1.30, and 0.94 respectively for radiate pine. These showed that D, G and I results were much encouraging than the recommended C as one of the national standards. The improvement in fire-retardant efficiency of the treated plywood on surface flammability for the three screened mixtures at 183.0 g/m^2 MUF spread amount were: 0.34-2.79 sec (kg/m^3)^(-1), 3.87-8.75°C．min (kg/m^3)^(-1), 1.45-2.08 (kg/m^3)^(-1), 2.40-3.93sec (kg/m^3)^(-1), and 0.23-0.39% (kg/m^3)^(-1), respectively when ignitability, heat re lease, smoke generation, afterflame time and weight loss percentage were considered. The application of G and I not only showed a better improving efficiency for the treated plywood in fire retardancy than current standard (C), their estimated least absorption amount required to meet the 3rd grade fire-retardant specification were also 15.1% less than that for C. Therefore the two screened fire retardants (G and I) formulated in this study are the best choice in terms of economics and fire-retardancy improvement.