Direct production of graphite fibrous materials from preoxidized acrylic fibrous materials

Claim 2

A process according to claim 1 wherein said preoxidized acrylic fibrous material is derived from an acrylonitrile copolymer which contains at least about 85 mol per cent of acrylonitrile units and up to about 15 mol per cent of one or more monovinyl units copolymerized therewith.

Claim 3

A process according to claim 1 wherein said preoxidized acrylic fibrous material is impregnated with said organic protective agent by immersion in the same.

Claim 4

A process according to claim 4 wherein said preoxidized acrylic fibrous material is immersed in a solvent containing said organic protective agent dissolved therein.

Claim 5

A process according to claim 1 wherein said organic protective agent is selected from the group consisting of organic phosphorus compounds, organic antimony compounds, organic tin compounds, halogenated alcohols, halogenated esters, halogenated organic acids, halogenated organic anhydrides, halogenated phenolic compounds, halogenated aliphatic hydrocarbons, halogenated aromatic hydrocarbons, halogenated aromatic ethers, silicone oils, and mixtures of the foregoing.

Claim 6

A process according to claim 1 wherein said reducing flame is generated by a fuel-oxidant mixture.

Claim 7

A process according to claim 7 wherein said oxidant is oxygen.

Claim 8

A process according to claim 8 wherein said fuel is acetylene.

Claim 9

A process according to claim 8 wherein said fuel is propane.

Claim 10

A process according to claim 7 wherein said impregnated fibrous material is passed through the luminous portion of said reducing flame.

Claim 11

A process according to claim 7 wherein the residence time of said impregnated fibrous material in said reducing flame is from about 2 to 24 seconds.

Claim 12

A process according to claim 9 wherein the residence time of said impregnated fibrous material in said reducing flame is from about 6 to 17 seconds.

Claim 13

A process according to claim 8 wherein the ratio of oxygen to fuel is such that the amount of oxygen is less than the stoichiometric amount required to completely oxidize said fuel.

Claim 14

A process according to claim 10 wherein an inert atmosphere is provided around said reducing flame.

Claim 15

A process according to claim 1 wherein said preoxidized acrylic fibrous material is a yarn.

Claim 16

A continuous process for producing a predominantly graphitic fibrous material from a preoxidized acrylic fibrous material derived from a fibrous precursor consisting primarily of recurring acrylonitrile units, said preoxidized acrylic fibrous material having a. a carbon content of up to about 65 per cent by weight, b. a relatively amorphous X-ray diffraction pattern, c. a bound oxygen content of at least about 7 per cent by weight, and d. an absence of structural integrity when heated for two seconds at a fiber temperature of 1,900* C., comprising: passing said preoxidized acrylic fibrous material through a zone containing an organic protective agent capable of rendering said material resistant to loss of structural integrity when Heated for at least two seconds at a fiber temperature of 1,900* C. selected from the group consisting of organic phosphorus compounds, organic antimony compounds, organic tin compounds, halogenated alcohols, halogenated esters, halogenated organic acids, halogenated organic anhydrides, halogenated phenolic compounds, halogenated aliphatic hydrocarbons, halogenated aromatic hydrocarbons, halogenated aromatic ethers, silicone oils, and mixtures of the foregoing, wherein said preoxidized acrylic fibrous material is impregnated with said organic protective agent, and passing said impregnated fibrous material through the luminous portion of a reducing flame generated by an acetylene-oxygen mixture imparting to said fibrous material a minimum temperature of at least 1,900* C. in which the ratio of oxygen to acetylene is less than the stoichiometric amount required to completely oxidize the acetylene for a residence time of about 2 to 24 seconds while said fibrous material is under a tension at least sufficient to prevent visible sagging.

Claim 17

A continuous process according to claim 17 wherein said preoxidized acrylic fibrous material is derived from an acrylonitrile homopolymer.

Claim 18

A continuous process according to claim 17 wherein said preoxidized acrylic fibrous material is derived from an acrylonitrile copolymer which contains at least about 85 mol per cent of acrylonitrile units and up to about 15 mol per cent of one or more monovinyl units copolymerized therewith.

Claim 19

A continuous process according to claim 17 wherein said preoxidized acrylic fibrous material is passed through a zone containing said organic protective agent dissolved in a solvent.

Claim 20

A continuous process according to claim 20 wherein said solvent is a halogenated hydrocarbon.

Claim 21

A continuous process according to claim 21 wherein said solvent is trichloroethylene.

Claim 22

A continuous process according to claim 17 wherein the residence for said impregnated fibrous material in said reducing flame is about 6 to 17 seconds.

Claim 23

A continuous process according to claim 17 wherein said preoxidized acrylic fibrous material is a yarn.