Patent ID: 7937924

Claim:
A method for producing a fire retardant and heat resistant yarn, said method comprising: providing an apparatus for converting a ribbon of tow into the yarn, said apparatus comprising a feed section including at least one spool removably mounted thereon, said feed section being operably coupled to a drafting section comprising a first pairs of rollers and a second pairs of rollers, said drafting section being operably coupled to a spinning section comprising at least one bobbin removably mounted thereon; providing a ribbon comprising a tow of oxidized PAN filaments on said at least one spool, said filaments being longitudinally aligned with one another in a generally flat and untwisted form; pulling said ribbon from said spool by unwinding and applying tension thereby maintaining said ribbon in said generally flat and untwisted form and feeding said generally flat and untwisted ribbon to said drafting component; stretching and breaking said filaments of said tow of oxidized PAN filaments to form a cohesive elongated network of fibers, in said drafting component by directing said ribbon through said first and second pairs of rollers while applying pressure to said first and second pairs of rollers, said first pair of rollers having substantially conterminous opposed surfaces and spinning at a first speed and said second pair of rollers being downstream and having substantially conterminous opposed surfaces and spinning at a second, faster speed, said pressure urging said second pair of rollers toward each other and said first pair of rollers toward each other; spinning and twisting said cohesive elongated network of fibers onto said bobbin thereby forming the yarn and wherein said spinning and twisting causes said yarn to have a twist count of about 100 twists per meter to about 800 twists per meter, and wherein said providing said ribbon, said pulling, said applying tension, said stretching and breaking and said spinning and twisting all take place in a single pass through said apparatus.