Manufacturing method of filter element for dust collector

Abstract

A method of manufacturing a filter element comprises the steps of mechanically crushing two grades or more of a heat resistive synthetic resin material, the grades having different melt flow indices, respectively, the heat resistive synthetic resin material being selected from the group consisting of polysulfone, polyethersulfone and polyphenylenesulfide or containing said selected heat resistive synthetic resin as a main constituent, mixing them with one grade of them being 20 to 80 wt %, sintering the mixture in a metal mold at a melt temperature thereof plus or minus 10.degree. C. when the mixture is crystalline resin or at a temperature in a range from glass transition temperature thereof up to the glass transition temperature plus 40.degree. C. when the mixture is non-crystalline resin to form a shaped product having intercommunicating porosity, spraying surfaces of the shaped product with a mixture in liquid suspension of polytetrafluoroethylene particles, adhesive comprising thermosetting synthetic resin, and water and solidifying the suspension by heating. In order to improve the wetting of polytetrafluoroethylene with water, ethyl alcohol may be added to the suspension medium.