Optically anisotropic melt forming aromatic copolyesters based on t-butylhydroquinone

Claim 2

A copolyester capable of forming an optically anisotropic melt consisting essentially of: I. An aromatic diol component consisting essentially of 95 to 55 mole % t-butylhydroquinone and 5 to 45 mole % of one or more polyaromatic diols; II. A dicarboxylic acid component selected from a "para"- or "metal"-oriented aromatic dicarboxylic or 1,4-cyclohexane dicarboxylic acid or mixtures thereof, provided that no more than 80 mole % of the dicarboxylic acid component comprises a napthalene dicarboxylic acid; and II. An aromatic hydroxycarboxylic acid component selected from 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid and 4-(4'-hydroxyphenyl)benzoic acid or mixtures thereof; where said copolyester contains equal chemical equivalents of components I and II and contains about 20 to 60 mole %, based on total moles I +II+III, of component III.

Claim 3

A copolyester of claim 1 in which the polyaromatic diol is selected from 4,4'-biphenol, bisphenol-A, 3-hydroxy-4'-(4-hydroxyphenyl)benzophenone, 2,6- or 2,7-dihydroxynaphthalene, 3,4'- or 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenylether and 4,4'-dihydroxydiphenylsulfide and mixtures thereof.

Claim 4

A copolyester of claim 2 in which the polyaromatic diol is 4,4'-biphenol or bisphenol-A.

Claim 5

A copolyester of claim 1, 2 or 3 where the aromatic diol consists of 95 to 75 mole % t-butylhydroquinone.

Claim 6

A copolyester of claim 4 where the aromatic diol consists of 90 to 80 mole % t-butylhydroquinone.

Claim 7

A copolyester of claim 1 or 2 where the dicarboxylic acid is selected from terephthalic acid, isophthalic acid, trans-1,4-cyclohexane dicarboxylic acid, 2,6-naphthalene dicarboxylic acid and mixtures thereof, provided that no more than about 50 mole % of the dicarboxylic acid is isophthalic acid and no more than about 60 mole % of the dicarboxylic acid is 2,6-napthalene dicarboxylic acid.

Claim 8

A copolyester of claim 6 where the dicarboxylic acid is terephthalic acid.

Claim 9

A copolyester of claim 1 or 2 which contains about 25 to 50 mole % of an aromatic hydroxycarboxylic acid selected from 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid and mixtures thereof.

Claim 10

A copolyester of claim 8 where the hydroxyacid is selected from 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid and mixtures thereof which mixtures contain at least about 85 mole % 4-hydroxybenzoic acid.

Claim 11

A copolyester of claim 8 which contains about 25 to 35 mole % of a hydroxyacid which is 4-hydroxybenzoic acid.

Claim 12

A polyester of claim 1 wherein the aromatic diol component (I) consists essentially of 95 to 75 mole % t-butylhydroquinone and 10 to 25 mole % of a diol selected from 4,4'-biphenol, bisphenol-A, 3-hydroxy-4'-(4-hydroxyphenyl)benzophenone, 2,6- or 2,7-dihydroxy-naphthalene, 3,4'- or 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenylether, 4,4'-dihydroxydiphenylsulfide and mixtures thereof; the aromatic diacid component (II) is selected from terephthalic acid, isophthalic acid, trans-1,4-cyclohexene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid and mixtures thereof, provided that no more than about 50 mole % of the dicarboxylic acid is isophthalic acid and no more than about 60 mole % of the dicarboxylic acid is 2,6-naphthalene dicarboxylic acid; the aromatic hydroxyacid component (III) is selected from 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid and mixtures thereof; and the copolyester contains about 25 to 50 mole %, based on total moles I+II+III, of component III.

Claim 13

A copolyester of claim 1 wherein the aromatic diol component (I) is 90 to 80 mole % t-butylhydroquinone and 10 to 20 mole % of 4,4'-biphenol or bisphenol-A; the aromatic diacid component (II) is terephthalic acid; and the aromatic hydroxyacid component (III) is 4-hydroxybenzoic acid; and said copolyester contains 25 to 35 mole %, based on total I+II+III, of 4-hydroxybenzoic acid.

Claim 14

A copolyester of any of claims 1, 11 or 12 which has an inherent viscosity of at least about 2 dL/g measured at 25° C. in a 50/50 by volume mixture of 1,2-dichloroethane and 4-chlorophenol.

Claim 15

A copolyester of claim 13 which either has a crystalline melting temperature below 350° C. or which has no crystalline melting temperature.

Claim 16

A shaped article obtained by extruding, compression molding or injection molding a copolyester of claim 1, 11 or 12.

Claim 17

A shaped article of claim 15 which is a film having a machine direction tensile modulus of at least about 1000 Kpsi and machine direction tensile strength of at least about 40 Kpsi, both measured at room temperature.

Claim 18

A shaped article of claim 15 which is a heat-treated fiber having a tenacity of at least about 20 g/d and an initial modulus of at least about 500 g/d, both measured at room temperature.

Claim 19

A shaped article of claim 15 which is a molded part having a flexural or tensile strength of at least about 15 Kpsi, and a flexural or tensile modulus of at least about 2000 Kpsi, both measured at room temperature.

Claim 20

A composite structure consisting essentially of (a) a copolyester of claim 1, 11 or 12 and (b) either of fibrous substrate or a particulate filler.

Claim 21

A composite structure consisting essentially of (a) one or more resins and (b) a fiber of a copolyester of claim 1, 11, or 12.

Claim 22

A process for preparing a copolyester of claim 1 comprising contacting under reaction conditions the diacetates of the aromatic diols, the mono-acetates of the hydroxyacid(s), and the dicarboxylic acid(s) in the desired quantities such that a molar excess of about 0.5 to 4 mole % of tert-butyhydroquinone is present and such that there are otherwise substantially equimolar quantities of acetate and carboxylic acid moieties.