Process for stabilizing polyarylates with an aromatic phenol

Claim 2

A process for preparing a melt stable polyarylate having a reduced viscosity of from about 0.4 to greater than 1.0 dl/gm, which process comprises reacting: (a) at least one diester derivative of a dihydric phenol having the following formula: ##STR14## wherein R is independently selected from an alkyl radical having from 1 to about 6 carbon atoms, or cycloalkyl having from 4 to about 7 carbon atoms, y is independently selected from alkyl groups of 1 to 4 carbon atoms, chlorine, or bromine, z independently has a value of from 0 to 4, inclusive, and R' is independently selected from a direct bond, a divalent saturated aliphatic hydrocarbon radical having 1 to 8 carbon atoms, a cycloalkylene or cycloalkylidene radical having up to and including 9 carbon atoms, O, S, SO, SO 2 , CO, x is 0 or 1; with (b) at least one aromatic dicarboxylic acid, at a temperature of from about 260° to about 350° C.; to form a polyarylate having a reduced viscosity of from about 0.5 to greater than 1.0 dl/g; and (c) adding a stabilizing amount of an aromatic phenol to the polyarylate to form a polyarylate substantially free of anhydride linkages; said aromatic phenol being free of substituents in at least one of the positions ortho to the hydroxy group.

Claim 3

A process as defined in claim 1 wherein the diester derivative of a dihydric phenol has the following formula: ##STR15##

Claim 4

A process as defined in claim 2 wherein each z is 0.

Claim 5

A process as defined in claim 1 wherein the aromatic dicarboxylic acid is a mixture of isophthalic acid and terephthalic acid.

Claim 6

A process as defined in claim 4 wherein the isophthalic acid to terephthalic acid ratio in the mixture is about 20:80 to about 100:0.

Claim 7

A process as defined in claim 1, 2, 3, 4 or 5 wherein the aromatic phenol is added in amounts of from 0.01 to about 10 mole percent, based on the amount of the starting materials.

Claim 8

A process as defined in claim 6 wherein the aromatic phenol is added in a solvent.

Claim 9

A process as defined in claim 6 wherein the aromatic phenol contains at least one and not more than three unhindered hydroxy groups.

Claim 10

A process as defined in claim 6 wherein the aromatic phenol is selected from p-phenyl phenol, p-cumylphenol, 4-hydroxybenzophenone, β-naphthol, hydroxy terminated polysulfone or hydroxy terminated polyethersulfone.

Claim 11

A process as defined in claim 1, 2, 3, 4 5, 6, 7, 8, or 9 wherein the reaction of the diester derivative of the dihydric phenol and aromatic dicarboxylic acid is carried out in the presence of from about 10 to about 60 weight percent, based on the weight of polyarylate produced, of a solvent.

Claim 12

A process as defined in claim 10 wherein the solvent is diphenyl ether.

Claim 13

A process as defined in claim 10 wherein the solvent is a cycloaliphatic, substituted aromatic, or heteroaromatic compound which contains at least one benzylic and/or tertiary hydrogen atom.

Claim 14

A process as defined in claim 12 wherein the solvent is selected from xylenes, cumene, diethybenzene, disopropyl benzene, tetrahydronaphthalene or decahydronaphthalene.

Claim 15

A process as defined in claim 1 wherein the reaction of the diester derivative of the dihydric phenol with the aromatic dicarboxylic acid is performed in the presence of a catalyst.

Claim 16

A process as defined in claim 14 wherein the catalyst is selected from magnesium, magnesium oxide and a magnesium or zinc salt of an inorganic acid, or organic acid, or mixtures thereof.

Claim 17

A process as defined in claim 15 wherein the catalyst is magnesium acetate.

Claim 18

A process as defined in claim 14, 15 or 16 wherein the catalyst is used in amounts of from about 1 to about 1000 parts per million, based on the weight of the polyarylate produced.

Claim 19

A process as defined in claim 1 which is carried out at a temperature of from about 275° to about 295° C.

Claim 20

A process as defined in claim 1 wherein the polyarylate produced has a reduced viscosity of from about 0.5 to about 0.8.

Claim 21

A process for preparing a melt stable polyarylate having a reduced viscosity of from about 0.4 to greater than 1.0 dl/gm which process comprises reacting: (a) an acid anhydride derived from an acid containing from 2 to 8 carbon atoms; (b) at least one dihydric phenol having the following formula: ##STR16## wherein y is independently selected from alkyl groups of 1 to 4 carbon atoms, chlorine or bromine, z independently has a value of from 0 to 4, inclusive and R' is independently selected from a direct bond, a divalent saturated hydrocarbon radical having 1 to 8 carbon atoms, a cycloalkylene or cycloalkylidene radical having up to and including 9 carbon atoms, O, S, SO, SO 2 , CO, x is 0 or 1; and (c) at least one aromatic dicarboxylic acid, at a temperature of from about 260° to about 350° C., to form a polyarylate having a reduced viscosity of from about 0.5 to greater than 1.0 dl/g; and (d) adding a stabilizing amount of an aromatic phenol to the polyarylate to form a polyarylate substantially free of anhydride linkages; said aromatic phenol being free of substituents in at least one of the positions ortho to the hydroxy group.

Claim 22

A process for preparing a melt stable polyarylate having a reduced viscosity of from about 0.4 to greater than 1.0 dl/gm which process comprises reacting: (a) an acid anhydride derived from an acid containing from 2 to 8 carbon atoms; (b) at least one dihydric phenol having the following formula: ##STR16## wherein y is independently selected from alkyl groups of 1 to 4 carbon atoms, chlorine or bromine, z independently has a value of from 0 to 4, inclusive and R' is independently selected from a direct bond, a divalent saturated hydrocarbon radical having 1 to 8 carbon atoms, a cycloalkylene or cycloalkylidene radical having up to and including 9 carbon atoms, O, S, SO, SO 2 , CO, x is 0 or 1; and (c) at least one aromatic dicarboxylic acid, at a temperature of from about 260° to about 350° C., to form a polyarylate having a reduced viscosity of from about 0.5 to greater than 1.0 dl/g; and (d) adding a stabilizing amount of an aromatic phenol to the polyarylate to form a polyarylate substantially free of anhydride linkages; said aromatic phenol being free of substituents in at least one of the positions ortho to the hydroxy group.

Claim 23

A process as defined in claim 20 wherein the acid anhydride is acetic anhydride.

Claim 24

A process as defined in claim 20 wherein the dihydric phenol has the following formula: ##STR17##

Claim 25

A process as defined in claim 22 wherein each z is 0.

Claim 26

A process as in claim 20, 21, 22, or 23 wherein the aromatic dicarboxylic acid is a mixture of isophthalic acid and terephthalic acid.

Claim 27

A process for preparing a melt stable polyarylate having a reduced viscosity of from about 0.4 to greater than 1.0 dl/gm, which process comprises the following steps: I. Forming a polyarylate prepolymer having a reduced viscosity of from about 0.1 to about 0.4 dl/gm by reacting: (a) at least one diester derivative of a dihydric phenol having the following formula: ##STR18## wherein R is independently an alkyl radical having from 1 to about 6 carbon atoms or cycloalkyl having from 4 to about 7 carbon atoms, y is independently selected from alkyl groups of 1 to 4 carbon atoms, chlorine, or bromine, z independently has a value of from 0 to 4, inclusive, and R' is independently selected from a direct bond, a divalent saturated aliphatic hydrocarbon radical having 1 to 8 carbon atoms, a cycloalkylene or cycloalkylidene radical having up to and including 9 carbon atoms, O, S, SO, SO 2 , CO, x is 0 or 1; with (b) at least one aromatic dicarboxylic acid at a temperature of from about 260° to about 350° C.: II. heating the prepolymer so formed in a vented extruder under vacuum at a temperature of from about 300° to about 350° C. for a period of time sufficient to form a polyarylate having a reduced viscosity of from about 0.5 to greater than 1.0 dl/g; and III. adding a stabilizing amount of an aromatic phenol to the polyarylate to form a polyarylate substantially free of anhydride linkages; said aromatic phenol being free of substituents in at least one of the positions ortho to the hydroxy group.

Claim 28

A process for preparing a melt stable polyarylate having a reduced viscosity of from about 0.4 to greater than 1.0 dl/gm, which process comprises the following steps: I. Forming a polyarylate prepolymer having a reduced viscosity of from about 0.1 to about 0.4 dl/gm by reacting: (a) at least one diester derivative of a dihydric phenol having the following formula: ##STR18## wherein R is independently an alkyl radical having from 1 to about 6 carbon atoms or cycloalkyl having from 4 to about 7 carbon atoms, y is independently selected from alkyl groups of 1 to 4 carbon atoms, chlorine, or bromine, z independently has a value of from 0 to 4, inclusive, and R' is independently selected from a direct bond, a divalent saturated aliphatic hydrocarbon radical having 1 to 8 carbon atoms, a cycloalkylene or cycloalkylidene radical having up to and including 9 carbon atoms, O, S, SO, SO 2 , CO, x is 0 or 1; with (b) at least one aromatic dicarboxylic acid at a temperature of from about 260° to about 350° C.: II. heating the prepolymer so formed in a vented extruder under vacuum at a temperature of from about 300° to about 350° C. for a period of time sufficient to form a polyarylate having a reduced viscosity of from about 0.5 to greater than 1.0 dl/g; and III. adding a stabilizing amount of an aromatic phenol to the polyarylate to form a polyarylate substantially free of anhydride linkages; said aromatic phenol being free of substituents in at least one of the positions ortho to the hydroxy group.

Claim 29

A polyarylate produced by the process of claim 1, 20 or 25.