Liquid crystalline polyesters
AssigneeMonsanto Company
InventorOliver D. Deex
Life of this patent
Estimating the term…
Abstract
Disclosed are liquid crystal copolyesters prepared from p-hydroxybenzoic acid, isophthalic and/or terephthalic acid, hydroquinone, and a mono-substituted hydroquinone wherein the substituent is selected from the group consisting of alkyls of 1 to 6 carbon atoms, phenyl and phenyl substituted with an alkyl of 1 to 6 carbon atoms, chloro, bromo, cyano, formyl, acetyl, and trifluoromethyl, wherein, when a specific amount of the hydroquinone is replaced by a specific substituted hydroquinone, the copolyester not only becomes more tractable but also unexpectedly more crystalline when compared to the unsubstituted copolyester.
Claims13
A copolyester capable of forming a thermotropic melt phase and having an inherent viscosity of at least about 0.3 measured at 30.degree. C. with a solution of 0.5 gm of copolyester per 100 m/ of a solvent composed of 60 weight % phenol and 40% tetrachloroethane, consisting essentially of the following divalent radicals:
- ##STR2## wherein the placements of the carbonyl groups of the B radicals are meta or para or a mixture of meta and para;
- wherein R is selected from the group consisting of alkyls of 1 to 6 carbon atoms, phenyl and phenyl substituted with an alkyl of 1 to 6 carbon atoms, chloro, bromo, cyano, formyl, acetyl, and trifluoromethyl;
- wherein the amount of radical A is in the range from about 10 mole % to about 60 mole % of the copolyester and wherein the amount of radical D is selected in the range from about 1 mole % up to about 50 mole % of the total amount of radicals C and D to provide a ratio of storage moduli of said copolyester determined at T.sub.g -50.degree. C. and T.sub.g +50.degree. C. less than the ratio of the storage moduli determined at T.sub.g -50.degree. C. and T.sub.g +50.degree. C. of a copolyester of identical composition except that the D radicals are replaced with C radicals.
Dependencies are inferred from the claim text.