US4497789A — Process for the manufacture of carbon fibers

Claim 1

Independent Claim 171 words

A process for the production of pitch fibers which are precursors readily convertible to carbon fibers or graphite fibers, comprising in combination the steps of: (a) obtaining a petroleum pitch derive from residuum from the catalytic cracking of petroleum, said pitch containing from about 20% to 40% alpha hydrogens and from 2% to about 15% of beta hydrogen atoms based on the total weight of the hydrogens in said pitch, said pitch having a softening point of at least about 250° C., a xylene insolubles content of about 15 to about 40% by weight, a quinoline insolubles content of about 0 to about 5% by weight, a sulfur content of about 0.1 to about 4% by weight, a coking value of about 65 to about 90 wt% and a mesophase content of about 0 to about 5% by weight; (b) melting said pitch and forming fibers therefrom; and (c) stabilizing said fibers by contact with oxidant for a time less than about 100 minutes at a temperature above about 285° C.

Claim 2

Dependent Claim 171 words

A process for the production of pitch fibers which are precursors readily convertible to carbon fibers or graphite fibers, comprising in combination the steps of: (a) obtaining a petroleum pitch derive from residuum from the catalytic cracking of petroleum, said pitch containing from about 20% to 40% alpha hydrogens and from 2% to about 15% of beta hydrogen atoms based on the total weight of the hydrogens in said pitch, said pitch having a softening point of at least about 250° C., a xylene insolubles content of about 15 to about 40% by weight, a quinoline insolubles content of about 0 to about 5% by weight, a sulfur content of about 0.1 to about 4% by weight, a coking value of about 65 to about 90 wt% and a mesophase content of about 0 to about 5% by weight; (b) melting said pitch and forming fibers therefrom; and (c) stabilizing said fibers by contact with oxidant for a time less than about 100 minutes at a temperature above about 285° C.

Claim 3

Dependent Claim 132 words

A process according to claim 1 wherein said pitch is prepared by a process comprising in combination the steps of: (a) thermally processing clarified slurry oil or cycle oil from which substantially all paraffins have been removed in a fluid catalytic cracking step and/or by extraction to produce a highly aromatic oil boiling at about 315° to 540° C.; (b) thermally cracking this highly aromatic oil at temperatures and pressures and for times sufficient to produce a thermally cracked petroleum pitch with a softening point of about 38.7° to about 126.7° C.; (c) subjecting the product of the preceding step to vacuum distillation at from about 0.1 to about 0.5 torr at a temperature of about 710° F. for a time in the range of from about 5 to about 15 seconds.

Claim 4

Dependent Claim 19 words

A process for manufacturing carbon fibers comprising carbonizing the stabilized fibers prepared according to the process of claim 1.

Claim 5

Dependent Claim 14 words

The process of claim 1 wherein the pitch fibers are prepared by melt blowing.

Claim 6

Dependent Claim 30 words

The process of claim 3 wherein the fibers are carbonized by heating them in an inert atmosphere to a temperature of about 900° to 1500° C. (1652° to 2732° F.).

Claim 7

Dependent Claim 30 words

The process of claim 3 wherein the fibers are carbonized by heating them in an inert atmosphere to a temperature of about 1000° to 3000° C. (1832° to 5432° F.).

Claim 8

Dependent Claim 60 words

The process for manufacturing carbon fibers comprising heating the pitch fibers of step b of claim 1 in an oxidizing environment to a first temperature that is about 6° to 11° C. (10° to 20° F.) below their glass transition temperature and then increasing the temperature to a higher temperature to render the fibers infusible and thereafter carbonizing the fibers.

Claim 9

Dependent Claim 53 words

The process of claim 1 in which the fibers of step b are heated in an oxidizing environment to a first temperature that is about 6° to 11° C. (10° to 20° F.) below their glass transition temperature and then the temperature is increased to a higher temperature to render the fibers infusible.

Claim 10

Dependent Claim 22 words

The process of claim 7 wherein the first temperature is about 175° C. and the higher temperature is above about 285° C.

Claim 11

Dependent Claim 21 words

The process of claim 8 wherein the first temperature is about 175° C. and the higher temperature is above 300° C.

Claim 12

Dependent Claim 72 words

The process of claim 1 in which the petroleum pitch of step A has a softening point of at least about 265° C. and in which the fibers are heated in step c in an oxidizing environment to a first temperature that is about 6° to 11° C. (10° to 20° F.) below their glass transition temperature and the temperature is then increased to a higher temperature to render the fibers infusible.

Claim 13

Dependent Claim 12 words

A process according to claim 1 in which the oxidant comprises air.

Claim 14

Dependent Claim 14 words

A process according to claim 1 in which the oxidant consists essentially of oxygen.

Claim 15

Dependent Claim 209 words

A process for the production of pitch fibers which are precursors readily convertible to carbon fibers and/or graphite fibers, comprising in combination the steps of: (a) thermally cracking and polymerizing a residuum from catalytic cracking of petroleum at temperatures and pressures and for times sufficient to produce a thermally cracked petroleum pitch with a softening point of about 38.7° to about 126.7° C.; (b) subjecting the product of the preceding step to vacuum distillation at from about 0.3 to about 0.5 torr at a temperature of above about 710° F. for a time in the range of from about 5 to about 15 seconds; (c) thereby obtaining a petroleum pitch having a softening point of at least about 250° C., a xylene insolubles content of about 15 to about 30% by weight, a quinoline insolubles content of about 0 to about 0.25% by weight, a sulfur content of about 0.1 to about 4% by weight, a coking value of about 70 to about 85 wt% and a mesophase content of about 0 to about 5% by weight; (d) melting said pitch and forming fibers therefrom; and (e) stabilizing said fibers by contact with oxidant for a time less than about 100 minutes at a temperature above about 285° C.

Claim 16

Dependent Claim 209 words

A process for the production of pitch fibers which are precursors readily convertible to carbon fibers and/or graphite fibers, comprising in combination the steps of: (a) thermally cracking and polymerizing a residuum from catalytic cracking of petroleum at temperatures and pressures and for times sufficient to produce a thermally cracked petroleum pitch with a softening point of about 38.7° to about 126.7° C.; (b) subjecting the product of the preceding step to vacuum distillation at from about 0.3 to about 0.5 torr at a temperature of above about 710° F. for a time in the range of from about 5 to about 15 seconds; (c) thereby obtaining a petroleum pitch having a softening point of at least about 250° C., a xylene insolubles content of about 15 to about 30% by weight, a quinoline insolubles content of about 0 to about 0.25% by weight, a sulfur content of about 0.1 to about 4% by weight, a coking value of about 70 to about 85 wt% and a mesophase content of about 0 to about 5% by weight; (d) melting said pitch and forming fibers therefrom; and (e) stabilizing said fibers by contact with oxidant for a time less than about 100 minutes at a temperature above about 285° C.

Claim 17

Dependent Claim 25 words

A process according to claim 14 wherein said residuum from the catalytic cracking of petroleum is derived from slurry oil, decant oil or cycle oil.

Claim 18

Dependent Claim 13 words

The process of claim 14 wherein the fibers are formed by melt blowing.

Claim 19

Dependent Claim 18 words

A process for manufacturing carbon fibers comprising carbonizing the pitch fibers produced by the process of claim 14.

Claim 20

Dependent Claim 24 words

The process of claim 14 in which the petroleum pitch recovered in step (c) has a softening point of at least about 265° C.

Claim 21

Dependent Claim 53 words

The process for manufacturing carbon fibers comprising heating the pitch fibers of claim 18 in an oxidizing environment to a first temperature that is about 6° to 11° C. below their glass transition temperature and the increasing the temperature to a higher temperature to render the fibers infusible and thereafter carbonizing the fibers.

Claim 22

Dependent Claim 14 words

The process of claim 19 wherein the pitch fibers are formed by melt blowing.

Claim 23

Dependent Claim 49 words

The process of claim 14 in which in step (e) the fibers are heated in an oxidizing environment to a first temperature that is about 6° to 11° C. below their glass transition temperature and then is increased the temperature to a higher temperature to render the fibers infusible.

Claim 24

Dependent Claim 21 words

The process of claim 21 wherein the first temperature is about 175° C. and the higher temperature is above 285° C.

Claim 25

Dependent Claim 21 words

The process of claim 21 wherein the first temperature is about 175° C. and the higher temperature is above 300° C.

Claim 26

Dependent Claim 25 words

The process of claim 21 wherein the first temperature is about 6° to 11° C. (10° to 20° F.) below the fibers' glass transition temperature.

Claim 27

Dependent Claim 18 words

A process for manufacturing carbon fibers comprising carbonizing the pitch fibers prepared by the process of claims 21.

Claim 28

Dependent Claim 24 words

The process of claim 25 wherein the fibers are carbonized by heating them in an inert atmosphere to a temperature of about 1200° C.

Claim 29

Dependent Claim 17 words

A process for manufacturing carbon fibers comprising carbonizing the fibers prepared by the process of claim 24.

Claim 30

Dependent Claim 14 words

The process of claim 24 wherein the pitch fibers are prepared by melt blowing.

Claim 31

Dependent Claim 30 words

The process of claim 27 wherein the fibers are carbonized by heating them in an inert atmosphere to a temperature of about 900° to 1500° C. (1652° to 2732° F.).

Claim 32

Dependent Claim 30 words

The process of claim 21 wherein the fibers are carbonized by heating them in an inert atmosphere to a temperature of about 1000° to 3000° C. (1832° to 5432° F.).

Claim 33

Dependent Claim 15 words

The process of claim 24 wherein the higher temperature is above 285° C. (545° F.).

Claim 34

Dependent Claim 72 words

The process of claim 14 in which the petroleum pitch recovered in step (c) has a softening point of at least about 265° C. and in which in step (e) the fibers are heated in an oxidizing environment to a first temperature that is about 6° to 11° C. (10° to 20° F.) below their glass transition temperatures and then increasing the temperature to a higher temperature to render the fibers infusible.

Claim 35

Dependent Claim 14 words

The process of claim 32 wherein the pitch fibers are prepared by melt blowing.

Claim 36

Dependent Claim 72 words

The process of claim 14 in which the petroleum pitch of step c has a softening point of at least about 265° C. and in which the fibers are heated in step e in an oxidizing environment to a first temperature that is about 6° to 11° C. (10° to 20° F.) below their glass transition temperature and the temperature is then increased to a higher temperature to render the fibers infusible.

Claim 37

Dependent Claim 12 words

A process according to claim 14 in which the oxidant comprises air.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1988-02-05	1988-08-06	1989-02-05	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1992-02-05	1992-08-06	1993-02-05	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1996-02-05	1996-08-06	1997-02-05	$7700.00	Window Closed / Lapsed

Process for the manufacture of carbon fibers

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