Patent ID: 7399522
Filing Date: 2008-07-15
Classification: B01D,B29C,Y10T

Abstract:
1. A heat-resistant filter element for separating and collecting particles from a dust gas, comprising: a permeable porous molding comprising particles of a resin composition in which the particles are fused to one another on the surface thereof, said fused portion including an antioxidant, wherein the resin particles have a fused surface portion and an unfused inner portion, said antioxidant being present in higher concentration in said fused portion than in said unfused portion, wherein the resin composition comprises a polyethylene as a main component of its resin ingredient and from 0.5 to 3 parts by weight of the antioxidant per 100 parts by weight of the resin ingredient; and a coating layer of a fluororesin formed on the surface of the permeable porous molding, said heat-resistant filter element prepared by: (I-1) dispersing a powdered antioxidant in resin particles comprising a polyethylene as a main component, (I-2) infiltrating the antioxidant into the resin particles comprising a polyethylene as a main component by heating to a temperature which is not lower than the melting point where the antioxidant liquefies and is in the range where the resin particles substantially retain their shape to prepare a particulate resin composition, (I-3) packing the particulate resin composition into a mold followed by heating to fusion-bond the resin composition particles to one another at the surface thereof to thereby form a permeable porous molding, and (I-4) forming a coating layer of a fluororesin on the surface of the permeable porous molding formed.