Method of making a bonded non-woven web

Claim 1

In a process for preparing a bonded nonwoven sheet wherein there is deposited on a moving belt a non-woven loose filamentary web of a mixture of about 70-95% by weight of polyethylene terephthalate matrix filaments and about 5-30% by weight of copolyester binder filaments, about 70-90% by weight of said copolyester comprising ethylene terephthalate repeating units and 10-30% by weight of the copolyester comprising ethylene isophthalate repeating units, the matrix filaments having a crystallinity index between 8 and 25%, the improvement comprising passing the deposited loose filamentary web under compressional restraint of about 0.2-2.0 lbs./in. 2 through saturated steam at practically atmospheric pressure for an exposure time of from 0.2 to 6 seconds to consolidate the web, removing the compressional restraint and forwarding the consolidated web to a bonding zone and finally heating the consolidated web in the bonding zone for an exposure time of from 0.2 to 6 seconds while the web is pressed against a porous surface with a flow of hot air through the web at a velocity of from 250 to 800 ft./min. and at a temperature of from 140° to 250° C.