Process for the continuous carbonization and graphitization of a stabilized acrylic fibrous material

Claim 2

A CONTINUOUS PROCESS FOR THE CARBONIZATION AND GRAPHIZATION OF A STABILZED ACRYLICFIBROUS MATERIAL WHICH IS NONBURNING WHEN SUBJECTED TO AN ORDINARY MATCH FLAME AND DERIVED FROM AN ACRYLIC FIBROUS MATERIAL SELECTED FROM THE GROUP CONSISTING OF AN ACRYLONITRILE HOMOPOLYMER AND ACRYLONITRILE COPOLYMERS WHICH CONTAIN AT LEAST ABOUT 85 MOL PERCENT OF ACRYLONITRILE UNITS AND UP TO ABOUT 15 MOL PERCENT OF ONE OR MORE MONOVINYL UNITS COPOLYMERIZED THEREWITH COMPRISING CONTINUOUSLY PASSING A CONTINUOUS LENGTH OF SAID FIBROUS MATERIAL THROUGH A HEATING ZONE OF A SINGLE INDUCTION FURNACE WHILE SAID FIBROUS MATERIAL IS SUSPENDED WITHIN THE CONFINS OF A HOLLOW GRAPHITE SUSCEPTOR WHICH IS INDUCTIVELY HEATED AND PROVIDED WITH AN INERT GASEOUS ATMOSPHERE AND A TEMPERATURE GRADIENT IN WHICH SAID FIBROUS MATERIAL IS INITIALLY RAISED FROM A TEMPERATURE WITHIN THE RANGE OF ABOUT 20* TO ABOUT 500*C WITHIN A PERION OF ABOUT 3 SECONDS TO ABOUT 10 MINUTES TO A TEMPERATURE WITHIN THE RANGE OF ABOUT 900* TO ABOUT 1600*C. WHERE IT IS MAINTAINED FOR ABOUT 3 SECONDS TO ABOUT 5 MINUTES TO FORM A CONTINUOUS LENGTH OF CARBONIZED FIBROUS MATERIAL, AND IN WHICH SAID CARBONIZED FIBROUS MATERIAL IS SUBSEQUENTLY RAISED TO A TEMPERATURE WITHIN THE RANGE OF ABOUT 2400* TO ABOUT 3100*C. TO FORM A CONTINUOUS LENGTH OF GRAPHITIZED FIBROUS MATERIAL.

Claim 3

A process according to claim 1 in which said stabilized acrylic fibrous material is derived from an acrylonitrile homopolymer.

Claim 4

A process according to claim 1 in which said stabilized acrylic fibrous material is derived from an acrylonitrile copolymer which contains at least about 95 mol per cent of acrylonitrile units and up to about 5 mol per cent of one or more monovinyl units copolymerized therewith.

Claim 5

A process according to claim 1 in which said continuous length of stabilized acrylic fibrous material is a yarn.

Claim 6

A process according to claim 1 in which said temperature gradient within said heating zone of said induction furnace initially raises said fibrous material within a period of about 3 seconds to about 5 minutes to a temperature within the range of about 900* to about 1600*C.

Claim 7

A process according to claim 1 in which said temperature gradient within said heating zone of said induction furnace initially raises said fibrous material within a period of about 3 seconds to about 5 minutes to a temperature within the range of about 1400* to about 1600*C.

Claim 8

A process according to claim 1 in which said temperature gradient within said heating zone of said induction furnace initially raises said fibrous material within a period of about 20 to about 60 seconds to a temperature within the range of about 1400* to about 1600*C.

Claim 9

A process according to claim 1 in which said temperature gradient within said heating zone of said induction furnace subsequently raises said carbonized fibrous material from a temperature within the range of about 900* to 1600*C. within a period of about 2 to about 30 seconds to a temperature within the range of about 2400* to about 3100*C. where it is maintained for about 10 seconds to about 1 minute.

Claim 10

A continuous process for the carbonization and graphitization of a stabilized acrylic fibrous material which is non-burning when subjected to an ordinary match flame and derived from an acrylic fibrous material selected from the group consisting of an acrylonitrile homopolymer and acrylonitrile copolymers which contain at least about 85 mol percent of acrylonitrile units and up to about 15 mol percent of one or more monovinyl units copolymerized therewith comprising continuously passing a continuous length of said fibrous material through a heating zone of a single induction furnace while said fibrous material is suspended within the confines of a hollow graphite susceptor which is inductively heated and provided with an inert gaseous atmosphere and a temperature gradient in which said fibrous material is initially raised from a temperature within the range of about 20* to about 500*C. within a period of about 20 to about 60 seconds to a temperature within the range of about 1400* to about 1600*C. where it is maintained for about 3 seconds to about 60 seconds to form a continuous length of carbonized fibrous material, and in which said carbonized fibrous material is subsequently raised from a temperature within the range of about 1400* to about 1600*C. within a period of about 2 to about 30 seconds to a temperature within the range of about 2400* to about 3100*C. where it is maintained for about 10 seconds to about 1 minute.

Claim 11

A continuous process for the carbonization and graphitization of a stabilized acrylic fibrous material which is non-burning when subjected to an ordinary match flame and derived from an acrylic fibrous material selected from the group consisting of an acrylonitrile homopolymer and acrylonitrile copolymers which contain at least about 85 mol percent of acrylonitrile units and up to about 15 mol percent of one or more monovinyl units copolymerized therewith comprising continuously passing a continuous length of said fibrous material through a heating zone of a single induction furnace while said fibrous material is suspended within the confines of a hollow graphite susceptor which is inductively heated and provided with an inert gaseous atmosphere and a temperature gradient in which said fibrous material is initially raised from a temperature within the range of about 20* to about 500*C. within a period of about 20 to about 60 seconds to a temperature within the range of about 1400* to about 1600*C. where it is maintained for about 3 seconds to about 60 seconds to form a continuous length of carbonized fibrous material, and in which said carbonized fibrous material is subsequently raised from a temperature within the range of about 1400* to about 1600*C. within a period of about 2 to about 30 seconds to a temperature within the range of about 2400* to about 3100*C. where it is maintained for about 10 seconds to about 1 minute.

Claim 12

A process according to claim 9 in which said stabilized acrylic fibrous material is derived from an acrylonitrile homopolymer.

Claim 13

A process according to claim 9 in which said stabilized acrylic fibrous material is derived from an acrylonitrile copolymer which contains at least about 95 mol percent of acrylonitrile units and up to about 5 mol percent of one or more monovinyl units copolymerized therewith.

Claim 14

A process according to claim 9 in which said stabilized acrylic fibrous material is yarn.

Claim 15

A process according to claim 9 in which said inert gaseous atmosphere is nitrogen.