Air filter and production method therefor

Abstract

An air filter comprising a laminate of a non-woven fabric made up of polyolefin fibers or polyester fibers or a composite of the non-woven fabrics and a PTFE porous film, wherein the amount of the total gases generated from the air filter is 20 μg/g by the analysis of gas chromatography. The amount of the gases generated from the air filter is greatly reduced by heat-treating the non-woven fabric at a temperature of from 80 to 130° C. for 5 minutes to 20 minutes before or after laminating with the PTFE porous film.

What is claimed is:  
     
         1 . An air filter comprising a laminate of a non-woven fabric made up of fibers containing at least one selected from polyolefins and polyesters as the main component or a composite composed of the non-woven fabrics and a polytetrafluoroethylene porous film, wherein the total amount of gases generated from the air filter is not more than 20 μg/g as a result of quantitative analysis by gas chromatography.  
     
     
         2 . An air filter of  claim 1 , wherein the non-woven fabric or the composite thereof is heat-treated.  
     
     
         3 . A production method of an air filter, which comprises heat-treating a non-woven fabric made up of fibers containing at least one kind selected from polyolefins and polyesters as the main component or a composite of the non-woven fabrics at a temperature of from 80° C. to 130° C. for from 5 minutes to 20 minutes and thereafter laminating the non-woven fabric or the composite thereof with a polytetrafluoroethylene porous film.  
     
     
         4 . A production method of an air filter, which comprises laminating a non-woven fabric made up of fibers containing at least one kind selected from polyolefins and polyesters as the main component or a composite of the non-woven fabrics and a polytetrafluoroethylene porous film, and thereafter heat-treating the resulting laminate at a temperature of from 80° C. to 130° C. for from 5 minutes to 20 minutes.