| 摘要 |
PURPOSE:To produce a filter which is high in collecting efficiency, is hardly clogged and is capable of holding a large amount of dust by a method wherein a gas containing a pulverized binder dispersed and suspended therein is passed through a web having a specified fiber density to generate a gradient of the amount of the binder adhered, and then the web is hot pressed. CONSTITUTION:The gas containing the pulverulent binder dispersed and suspended therein is passed through the web having a fiber density of 7X10<-4>-1X10<-2> at a velocity of not higher than 4m/sec. By this operation, the binder is adhered to the wen in an amount of 10-80wt% of the weight of the web, in such a manner that the binder is abundantly adhered on the face layer side of the web and is lean on the back layer side. Then, the web with the binder is heated to a temperature of not lower than the melting point of the binder and is hot pressed so as to attain a filter density of up to 0.2. Subsequently, the pressure for hot pressing is released to make the web recover from the compressed state. Thus, the side of the web where the binder is lean is provided with a lower fiber density and this side is used as a inflow side for dust-containing air, while the other side of the web is used as a discharge side. |
