ポリエステル繊維を含む綿の燻焼の挙動

抄録

Smoldering of a futon, a Japanese style mattress, is significantly affected by the blend ratio of polyester and cotton fibers comprising the wad that is stuffed in the futon; it was found that the smoldering is inhibited when a relatively small amount of polyester fibers is added to the wad. To understand this effect of blend ratio, experiments are conducted in this study with bare wads of cotton and polyester fibers having different blend ratios. A thin wad is laid on a hot plate with the intention of compensating the heat loss and letting the smoldering occur within the visible range in the wad so that the behavior of it can be observed from the surface. A spot of its surface is heated locally with a lamp and the temperature is measured by means of a thermographic camera for detecting the ignition. After it ignites, the smoldering behavior is recorded by a video camera or a microscope. It is found that the average of the ignition delay time increases as the polyester ratio increases, while data scatter widely depending on each sample. All the wad samples containing 25wt.% of polyester ignite just as those of 100wt.% cotton fibers, but the travel distances of the smoldering spread become distinctly shorter. These results indicate that the inhibition of the smoldering with small amount of polyester is originated from not the propensity of ignition but the propensity of smoldering spread. The microscopic observation reveals a vast movement of fibers in the preheating zone, which is caused by the melting and deformation of polyester fibers; such a movement may influence the propensity of the smoldering spread.