Table 2.
Treatment method of flame retardant.

Treatment method	Treatment condition
Spreading method	The specimen was brushed with flame retardant liquid. And then the conditions of the specimen and of the environment were the following: temperature 23 °C, relative humidity 50% during 24 h. The process was repeated three times.
Impregnation method	Each of specimens were immersed in flame retardant liquid for 10, 30, 60, 90, 120, 240 min. The conditions of the specimen and of the environment were the following: temperature 23 °C, relative humidity 50%.