Filter element and process for producing the same
The present invention provides a filter element and a method for producing the same, which do not generate pollution during waste disposal, can be easily produced, improve the pressure loss and reduce the production cost. The filter element and the method for producing the same are characterized in that ultrahigh molecular weight polyethylene fine powders, which have an average molecular weight of 3,000,000 to 11,000,000 and a bulk specific gravity of 0.15 to 0.29, are the aggregate of primary particles, and are shaped to have voids of 1 to 5 μm in a part where the primary particles are connected, are filled into the pores on the surface of a filter element base made of an open-cell porous molded body prepared by heating and sintering synthetic resin powders, a non-woven fabric or a felt.
1. A filter element for separating solid particles from a fluid containing the solid particles, which comprises an open-cell porous molded body as a filter element base and ultrahigh molecular weight polyethylene fine powders,
wherein the ultrahigh molecular weight polyethylene fine powders have an average molecular weight of 3,000,000 to 11,000,000 and a bulk specific gravity of 0.15 to 0.29;
wherein the ultrahigh molecular weight polyethylene fine powders form an aggregate of primary particles, wherein the aggregates are in the shape of a bunch of grapes or a cauliflower, and wherein the aggregates have voids of 1 to 5 μm in a part where the primary particles are connected; and
wherein the ultrahigh molecular weight polyethylene fine powders are filled in or coated into pores on the surface of the open-cell porous molded body; wherein the open-cell porous molded body is prepared by heating and sintering synthetic resin powders, a non-woven fabric or a felt.
2. The filter element according to claim 1 , wherein the ultrahigh molecular weight polyethylene fine powders have an average particle size of from 3 to 150 μm.
3. The filter element according to claim 1 , wherein the ultrahigh molecular weight polyethylene fine powder further contains an antioxidant, which is impregnated into the ultrahigh molecular weight polyethylene find powder by heating, to improve its heat resistance.
4. A method for producing a filter element for separating solid particles from a fluid containing the solid particles, which comprises
providing a filter element base by heating and sintering synthetic resin powders, a non-woven fabric or a felt to produce an open-cell porous molded body; and
applying a suspension solution containing ultrahigh molecular weight polyethylene fine powders, water, and a water-dispersible binder to the surface of the open-cell porous molded body, followed by heating,
wherein the ultrahigh molecular weight polyethylene fine powders, have an average molecular weight of 3,000,000 to 11,000,000 and a bulk specific gravity of 0.15 to 0.29;
wherein the ultrahigh molecular weight polyethylene fine powders are in the form of an aggregate of primary particles, wherein the aggregates are in the shape of a bunch of grapes or a cauliflower, and have voids of 1 to 5 μm in a part wherein the primary particles are connected.