Melt-fusible polyimides

Claim 2

A substantially void-free composite structure consisting essentially of a fibrous substrate impregnated with a melt-fusible polyimide containing up to about 10% of end-capped amino or anhydride groups and consisting essentially of the following repeating units: ##STR15## where Q in each repeating unit, independently of any other unit, is a divalent organic radical selected from the following: ##STR16## where G is O or S; and Z is hydrogen or phenyl; and, when Z is hydrogen, both terminal covalent bonds are either in the ortho or meta position with respect to G; while, when Z is phenyl, both terminal covalent bonds are in ortho, meta, or para position with respect to G; ##STR17## where G is O or S; and R is phenyl, biphenyl, or naphthyl; and ##STR18## where G is O or S.

Claim 3

A composite structure of claim 1 wherein G in each repeating unit Q is O.

Claim 4

A composite of claim 2 wherein Q is a divalent radical remaining on removal of the amino groups from the diamine: H 2 N--Q--NH 2 selected from the group consisting of: 1,3-bis(2-aminophenoxy)benzene, 1,2-bis(3-aminophenoxy)benzene, 1,2-bis(2-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(2-aminophenoxy)benzene, 2,4-diaminodiphenyl ether, 1-(2,4-diaminophenoxy)naphthalene, 2-(2,4-diaminophenoxy)naphthalene, 2-(2,4-diaminophenoxy)biphenyl, 4-(2,4-diaminophenoxy)biphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)-2-phenylbenzene, 2,2-bis[4-(2-aminophenoxy)phenyl]propane, and 2,2-bis[4-(3-aminophenoxy)phenyl]propane.

Claim 5

A composite of claim 3 wherein H 2 N--Q--NH 2 is selected from the group consisting of:

Claim 6

3-bis(3-aminophenoxy)benzene, 1,3-bis(2-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)-2-phenylbenzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, and 2-(2,4-diaminophenoxy)biphenyl.

Claim 7

3-bis(3-aminophenoxy)benzene, 1,3-bis(2-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)-2-phenylbenzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, and 2-(2,4-diaminophenoxy)biphenyl.

Claim 8

A composite of claim 4 wherein the repeating unit of the polyimide is of two types, H 2 N--Q--NH 2 for one type being 1,3-bis(3-aminophenoxy)benzene and for the other type 2,2-bis[4-(4-aminophenoxy)phenyl]propane, both types being present.

Claim 9

A composite structure which is a substantially void-free prepreg consisting essentially of a fibrous substrate impregnated with a concentrated solution of a polyamide acid, which is a precursor of a melt-fusible polyimide, the volatiles content of the prepreg being at most about 25% of its total weight, the melt-fusible polyimide which can be obtained by heating the precursor to a sufficiently high temperature consisting essentially of the following repeating units: ##STR19## where Q in each repeating unit, independently of any other unit, is a divalent organic radical selected from the following: ##STR20## where G is O or S, and Z is hydrogen or phenyl; and, when Z is hydrogen, both terminal covalent bonds are either in the ortho or meta position with respect to G; while, when Z is phenyl; both terminal covalent bonds are in ortho, meta, or para position with respect to G; ##STR21## where G is O or S; and R is phenyl, biphenyl, or naphthyl; and ##STR22## where G is O or S.

Claim 10

A composite structure which is a substantially void-free prepreg consisting essentially of a fibrous substrate impregnated with a concentrated solution of a polyamide acid, which is a precursor of a melt-fusible polyimide, the volatiles content of the prepreg being at most about 25% of its total weight, the melt-fusible polyimide which can be obtained by heating the precursor to a sufficiently high temperature consisting essentially of the following repeating units: ##STR19## where Q in each repeating unit, independently of any other unit, is a divalent organic radical selected from the following: ##STR20## where G is O or S, and Z is hydrogen or phenyl; and, when Z is hydrogen, both terminal covalent bonds are either in the ortho or meta position with respect to G; while, when Z is phenyl; both terminal covalent bonds are in ortho, meta, or para position with respect to G; ##STR21## where G is O or S; and R is phenyl, biphenyl, or naphthyl; and ##STR22## where G is O or S.

Claim 11

A composite structure of claim 6 wherein G in each repeating unit Q is O.

Claim 12

A prepreg of claim 6 wherein Q is a divalent radical remaining on removal of the amino groups from a diamine H 2 N--Q--NH 2 selected from the group consisting of: 1,3-bis(2-aminophenoxy)benzene, 1,2-bis(3-aminophenoxy)benzene, 1,2-bis(2-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(2-aminophenoxy)benzene, 2,4-diaminodiphenyl ether, 1-(2,4-diaminophenoxy)naphthalene, 2-(2,4-diaminophenoxy)naphthalene, 2-(2,4-diaminophenoxy)biphenyl, 4-(2,4-diaminophenoxy)biphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(2-aminophenoxy)phenyl]propane

Claim 13

4-bis(4-aminophenoxy)-2-phenylbenzene.

Claim 14

4-bis(4-aminophenoxy)-2-phenylbenzene.

Claim 15

A prepreg of claim 8, wherein the repeating unit of the polyimide is of two types, H 2 N--Q--NH 2 for one type being 1,3-bis(3-aminophenoxy)benzene and for the other type 2,2-bis[4-(4-aminophenoxy)phenyl]propane, both types being present.

Claim 16

A composite structure selected from the composites of any one of the claims 1-9 and prepregs of any of the claims 6-9, wherein the fibrous substrate is a preformed woven, non-woven, or felted material.

Claim 17

A composite structure of claim 10 wherein the fibrous substrate is in the form of unidirectional continuous fibers.

Claim 18

A composite structure of any one of the claims 1-11, wherein the fibrous substrate is selected from the group consisting of carbon, aramid, glass, boron, and asbestos fibers.

Claim 19

A composite structure of any one of the claims 1-12 wherein the fiber content is about 40-65 volume percent.

Claim 20

A composite structure of any one of the claims 1-13, which is in tape form.

Claim 21

A shaped article formed from any one of the composite structures of claims 1-14.

Claim 22

A melt-fusible polyimide consisting essentially of the following repeating units ##STR23## where Q in each repeating unit, independently of any other unit, is a divalent organic radical selected from the following: ##STR24## where G is O or S, and Z is hydrogen or phenyl; and, when Z is hydrogen, both terminal covalent bonds are either in the ortho or meta position with respect to G; while, when Z is phenyl, both terminal covalent bonds are in ortho, meta, or para position with respect to G; ##STR25## where G is O or S; and R is phenyl, biphenyl, or naphthyl; and ##STR26## where G is O or S and both terminal covalent bonds are in the ortho or meta position with respect to G.

Claim 23

A melt-fusible polyimide consisting essentially of the following repeating units ##STR23## where Q in each repeating unit, independently of any other unit, is a divalent organic radical selected from the following: ##STR24## where G is O or S, and Z is hydrogen or phenyl; and, when Z is hydrogen, both terminal covalent bonds are either in the ortho or meta position with respect to G; while, when Z is phenyl, both terminal covalent bonds are in ortho, meta, or para position with respect to G; ##STR25## where G is O or S; and R is phenyl, biphenyl, or naphthyl; and ##STR26## where G is O or S and both terminal covalent bonds are in the ortho or meta position with respect to G.

Claim 24

A polyimide of claim 16 wherein G in each repeating unit Q is O.

Claim 25

A polyimide of claim 17, wherein Q is the radical remaining on removal of the amino groups from a diamine H 2 N--Q--NH 2 selected from the group consisting of: 1,3-bis(2-aminophenoxy)benzene, 1,2-bis(3-aminophenoxy)benzene, 1,2-bis(2-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(2-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 2,4-diaminodiphenyl ether, 1-(2,4-diaminophenoxy)naphthalene, 2-(2,4-diaminophenoxy)naphthalene, 2-(2,4-diaminophenoxy)biphenyl, 4-(2,4-diaminophenoxy)biphenyl, 1,4-bis(4-aminophenoxy)-2-phenylbenzene, and 2,2-bis[4-(2-aminophenoxy)phenyl]propane.

Claim 26

A polyimide of claim 18 wherein Q is the radical remaining on removal of the amino groups from a diamine H 2 N--Q--NH 2 selected from the group consisting of: 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(2-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)-2-phenylbenzene, 2,2-bis[4-(2-aminophenoxy)phenyl]propane, and 2-(2,4-diaminophenoxy)biphenyl.

Claim 27

A polyimide of claim 19, wherein the repeating unit is of two types, H 2 N--Q--NH 2 for one type being 1,3-bis(3-aminophenoxy)benzene and for the other type being 2,2-bis[4-(4-aminophenoxy)-phenyl]propane, both types being present.

Claim 28

A polyimide of claim 17 which contains an excess of up to 10% of diamine H 2 N--Q--NH 2 .

Claim 29

A polyimide of claim 21 wherein the excess of diamine is end-capped.

Claim 30

A polyimide of claim 17 which contains an excess of up to 10% of pyromellitic dianhydride.

Claim 31

A polyimide of claim 23 wherein the excess of dianhydride is end-capped.

Claim 32

A polyimide of claim 17 which is melt-processible.

Claim 33

An article obtained by extruding, compression-molding, or injection-molding a polyimide of claim 25.

Claim 34

A monofilament or fiber made from a polyimide of claim 25.

Claim 35

A polyimide of any one of the claims 16-25 which has reversible crystallinity.

Claim 36

A film of a polyimide of any one of the claims 16-25.

Claim 37

A polyimide composition comprising a polyimide of claim 16 containing a reinforcing additive in fiber or particulate form.

Claim 38

A polyimide composition of claim 30, wherein the volume proportion of reinforcing additive is 5-70%.

Claim 39

A composition of claim 31 wherein the volume proportion of reinforcing additive is 5-50%.

Claim 40

A composition of claim 32 wherein the volume proportion of reinforcing additive is 5-25%.

Claim 41

A solution in a polar solvent of a pyromellitic diester diacid and of a diamine, either component being present in a 0-10% molar excess, the diamine being either a single species or more than one species selected from the following classes (a) through (c): ##STR27## where G is O or S, and Z is hydrogen or phenyl; and, when Z is hydrogen, both terminal amine groups are either in the ortho or meta position with respect to G; while, when Z is phenyl, both terminal amine groups are in ortho, meta, or para position with respect to G; ##STR28## where G is O or S; and R is phenyl, biphenyl, or naphthyl; and ##STR29## where G is O or S, and both amine groups are in the ortho or meta position with respect to G.

Claim 42

A solution in a polar solvent of a pyromellitic diester diacid and of a diamine, either component being present in a 0-10% molar excess, the diamine being either a single species or more than one species selected from the following classes (a) through (c): ##STR27## where G is O or S, and Z is hydrogen or phenyl; and, when Z is hydrogen, both terminal amine groups are either in the ortho or meta position with respect to G; while, when Z is phenyl, both terminal amine groups are in ortho, meta, or para position with respect to G; ##STR28## where G is O or S; and R is phenyl, biphenyl, or naphthyl; and ##STR29## where G is O or S, and both amine groups are in the ortho or meta position with respect to G.

Claim 43

A solution of claim 34 wherein G in each repeating unit Q is O.

Claim 44

A solution of claim 35 wherein the diamine is selected from the group consisting of:

Claim 45

3-bis(2-aminophenoxy)benzene, 1,2-bis(3-aminophenoxy)benzene; 1,2-bis(2-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(2-aminophenoxy)benzene, 2,4-diaminodiphenyl ether, 1-(2,4-diaminophenoxy)naphthalene, 2-(2,4-diaminophenoxy)naphthalene, 2-(2,4-diaminophenoxy)biphenyl, 4-(2,4-diaminophenoxy)biphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(2-aminophenoxy)phenyl]propane, and 1,4-bis(4-aminophenoxy)-2-phenylbenzene.

Claim 46

3-bis(2-aminophenoxy)benzene, 1,2-bis(3-aminophenoxy)benzene; 1,2-bis(2-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(2-aminophenoxy)benzene, 2,4-diaminodiphenyl ether, 1-(2,4-diaminophenoxy)naphthalene, 2-(2,4-diaminophenoxy)naphthalene, 2-(2,4-diaminophenoxy)biphenyl, 4-(2,4-diaminophenoxy)biphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(2-aminophenoxy)phenyl]propane, and 1,4-bis(4-aminophenoxy)-2-phenylbenzene.

Claim 47

A solution of claim 36 wherein two diamines are present, one diamine being 1,3-bis(3-aminophenoxy)benzene and the other 2,2-bis[4-(4-aminophenoxy)phenyl]propane.

Claim 48

A composite structure which is a substantially void-free prepreg consisting essentially of a fibrous substrate impregnated with a concentrated solution of claim 34, the volatiles content of the prepreg being at most about 25% of its total weight.

Claim 49

A composite structure which is a substantially void-free prepreg consisting essentially of a fibrous substrate impregnated with a concentrated solution of claim 36 the volatiles content of the prepreg being at most about 25% of its total weight.

Claim 50

A composite structure which is a substantially void-free prepreg consisting essentially of a fibrous substrate impregnated with a concentrated solution of claim 37, the volatiles content of the prepreg being at most about 25% of its total weight.

Claim 51

A diamine selected from the class consisting of: 1,4-bis(4-aminophenoxy)-2-phenylbenzene; 2-(2,4-diaminophenoxy)biphenyl; and 4-(2,4-diaminophenoxy)biphenyl.

Claim 52

A diamine selected from the class consisting of: 1,4-bis(4-aminophenoxy)-2-phenylbenzene; 2-(2,4-diaminophenoxy)biphenyl; and 4-(2,4-diaminophenoxy)biphenyl.

Claim 53

A diamine of claim 41 which is 1,4-bis(4-aminophenoxy)-2-phenylbenzene.

Claim 54

A diamine of claim 41 which is 2-(2,4-diaminophenoxy)biphenyl.

Claim 55

A diamine of claim 41 which is 4-(2,4-diaminophenoxy)biphenyl.